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  • 1. Aaditya, V. B.
    et al.
    Bharathesh, Badada Math
    KTH.
    Harshitha, R.
    Chaluvaraju, B. V.
    Raghavendra, U. P.
    Murugendrappa, M. V.
    Study of dielectric properties of polypyrrole/titanium dioxide and polypyrrole/titanium dioxide-MWCNT nano composites2018In: Journal of materials science. Materials in electronics, ISSN 0957-4522, E-ISSN 1573-482X, Vol. 29, no 4, p. 2848-2859Article in journal (Refereed)
    Abstract [en]

    The polypyrrole/titanium dioxide nano composites and polypyrrole/titanium dioxide-MWCNT nano composites were synthesized by chemical polymerization technique in the presence of an ammonium persulphate (oxidizing agent). Different concentrations viz. 15, 30, 45 and 60 wt% of titanium dioxide (TiO2) as well as mixture of TiO2-MWCNT in polypyrrole (PPy) respectively were used in the present study. The nano composites have almost spherical type shaped particles which have cluster formation as confirmed from SEM photos. The XRD graphs reveal that the PPy/TiO2 (PT) nano composites have shown the semi-crystalline nature and also, the graphs indicate the changeover of the structure of PPy/TiO2-MWCNT (PTM) nano composites from amorphous to semi-crystalline nature. From the FTIR figures, shift in wavenumber towards lower side is noticed in the case of PT and PTM nano composites when compared to PPy. The dielectric properties such as dielectric constant, dielectric loss and tangent loss have shown good behavior. This reveals that, the TiO2 as well as mixture of TiO2-MWCNT particles have shown strong dependence on PPy and helps to form good composites. So, the nano composites are good dielectric materials.

  • 2. Abbasi, Alireza
    et al.
    Geranmayeh, Shokoofeh
    Skripkin, Mikhail Y.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Potassium ion-mediated non-covalent bonded coordination polymers2012In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 41, no 3, p. 850-859Article in journal (Refereed)
    Abstract [en]

    Crystal structures and vibrational spectra of three related network-forming coordination complexes have been studied. Two novel thermodynamically stable pseudo-polymorphic solvated rhodium chloro compounds, [cis-RhCl4(DMSO-kappa S)(2)K](n), 1, and [cis-RhCl4(DMSO-kappa S)(2)K center dot 3H(2)O](n), 2, and one metastable compound [trans-RhCl4(DMSO-kappa S)(2)K center dot 0.25H(2)O](n), 3, crystallize at ambient temperature in the orthorhombic space group P2(1)2(1)2(1) for 1, and the monoclinic space groups P2(1)/n and P2(1)/c for 2 and 3, respectively. All three structures contain [RhCl4(DMSO-kappa S)(2)]-complexes in which the rhodium(III) ions bind to two dimethyl sulfoxide (DMSO) sulfur atoms and four chloride ions in distorted octahedral coordination geometries. The complexes are connected in networks via potassium ions interacting with the Cl- and the DMSO oxygen atoms. As the sum of Shannon ionic radii of K+ and Cl- exceeds the K-Cl distances in compounds under study, these compounds can be described as Rh-Cl-K coordination polymers with non-covalent bonding, which is not common in these systems, forming 1- and 2-D networks for 1/2 and 3, respectively. The 2-D network with nano-layered sheets for compound 3 was also confirmed by TEM images. Further evaluation of the bonding in the cis- and trans-[RhCl4(DMSO-kappa S)(2)](-) entities was obtained by recording Raman and FT-IR absorption spectra and assigning the vibrational frequencies with the support of force-field calculations. The force field study of complexes reveals the strong domination of trans-effect (DMSO-kappa S > Cl) over the effect of non-covalent bonding in coordination polymeric structures. The comparison of calculated RhCl, RhS and SO stretching force constants showed evidence of K+-ligand interactions whereas direct experimental evidences of K+-Cl- interaction were not obtained because of strong overlap of the corresponding spectral region with that where lattice modes and Rh-ligand bendings appear.

  • 3.
    Abdala, Esraa
    et al.
    Department of Chemical Engineering, University of Khartoum, Khartoum, Sudan.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Mustafa, Mustafa A.
    Materials and Nanotechnology Research Centre, University of Khartoum, Khartoum, Sudan.
    Efficient Biodiesel Production from Algae Oil Using Ca-Doped ZnO Nanocatalyst2020In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 59, no 43, p. 19235-19243Article in journal (Refereed)
    Abstract [en]

    Biodiesel is a sustainable alternative to petroleum diesel produced by transesterification of vegetable oils in the presence of a catalyst. The present study investigates heterogeneous transesterification of algal oil to biodiesel using novel calcium-doped zinc oxide nanocatalysts synthesized using a UV shaker. The developed catalyst was under different light sources, UV and non-UV; different calcium concentrations (0.01, 0.03, 0.05 M); and different calcination temperatures (600, 700, 800 degrees C). The catalyst has been characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and energy-dispersive spectroscopy (EDS). The effects of the different parameters used in catalyst preparation were studied for transesterification of algal oil. The catalyst of 0.05 M calcium loading and 700 degrees C calcination temperature synthesized in UV light is considered as the most suitable nanocatalyst, which achieved 99.18% yield of biodiesel. The catalyst was used three times effectively with 76% yield. The chemical properties of biodiesel have been investigated using gas chromatography (GC).

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  • 4.
    Abdel-Baset, T. A.
    et al.
    Taibah Univ, Fac Sci, Dept Phys, Yanbu 46423, Saudi Arabia.;Fayoum Univ, Fac Sci, Dept Phys, Al Fayyum 63514, Egypt..
    Abdel-Hafiez, Mahmoud
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Effect of metal dopant on structural and magnetic properties of ZnO nanoparticles2021In: Journal of materials science. Materials in electronics, ISSN 0957-4522, E-ISSN 1573-482X, Vol. 32, no 12, p. 16153-16165Article in journal (Refereed)
    Abstract [en]

    Zn1-xRxO (R = Li, Mg, Cr, Mn, Fe and Cd) were obtained by using co-precipitation synthesis technique with constant weight percent of 3% from R ions. The phase composition, crystal structure, morphology, density functional theory (DFT), and magnetic properties were examined to comprehend the influence of Zn2+ partial substitution with R ions. X-ray diffraction shows that the ZnO lattice parameters were slightly affected by R doping and the doped sample crystallinity is enhanced. Our results show that introducing Cr, Mn and Fe along with Mg into ZnO induces a clear magnetic moment without any apparent distortion in the structural morphology. The spatial configuration of dopant atoms is determined from first-principles calculations, giving a better understanding of the position of the dopant atom responsible for the magnetism. The magnetic moments obtained from our calculations are 3.67, 5.0, and 4.33 mu B per dopant atom for Cr, Mn, and Fe, respectively, which agree with the experimental values. While Cr and Fe tend to form clusters, Mn has more propensity to remain evenly distributed within the system, avoiding cluster-derived magnetism.

  • 5.
    Abdelhamid, Hani Nasser
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Assiut University, Egypt; The British University in Egypt, Egypt.
    MOFTextile: Metal-organic frameworks nanosheets incorporated cotton textile for selective vapochromic sensing and capture of pyridine2023In: Applied organometallic chemistry, ISSN 0268-2605, E-ISSN 1099-0739, Vol. 37, no 5, article id e7078Article in journal (Refereed)
    Abstract [en]

    Metal–organic frameworks (MOFs) improved several trends and are promising for industrial applications. However, current synthesis processes offer powder form, rendering their applications difficult. A simple solvothermal method offered an in situ growth of copper-based MOFs, for example, CuBDC (BDC: benzene-1,4-dicarboxylic acid) into a cotton textile; the material was denoted as CuBDC@Textile. CuBDCTextile was used as a solid sensor and adsorbent for volatile organic compounds (VOCs). It exhibited good vapochromic properties that enabled a colorimetric detection of pyridine (Py) via naked eyes with high selectivity and good sensitivity. Adsorption of pyridine via pervaporation using CuBDC@Textile was recorded. CuBDCTextile is a flexible textile with a high adsorption capacity (137.9 mg g−1) toward pyridine. It offered dual functional: sensor probe and adsorbent. The synthesis of CuBDC@Textile and their excellent performance as a sensor and adsorbent are promising for further investigation of the “MOFs on textile materials” topic.

  • 6.
    Abdelhamid, Hani Nasser
    et al.
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden;Assiut Univ, Dept Chem, Adv Multifunct Mat Lab, Assiut 71515, Egypt.
    El-Zohry, Ahmed M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Cong, Jiayan
    KTH Royal Inst Technol, Dept Chem, Appl Phys Chem, Tekn Ringen 30, S-10044 Stockholm, Sweden.
    Thersleff, Thomas
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.
    Karlsson, Martin
    KTH Royal Inst Technol, Dept Chem, Appl Phys Chem, Tekn Ringen 30, S-10044 Stockholm, Sweden.
    Kloo, Lars
    KTH Royal Inst Technol, Dept Chem, Appl Phys Chem, Tekn Ringen 30, S-10044 Stockholm, Sweden.
    Zou, Xiaodong
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.
    Towards implementing hierarchical porous zeolitic imidazolate frameworks in dye-sensitized solar cells2019In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 7, article id 190723Article in journal (Refereed)
    Abstract [en]

    A one-pot method for encapsulation of dye, which can be applied for dye-sensitized solar cells (DSSCs), and synthesis of hierarchical porous zeolitic imidazolate frameworks (ZIF-8), is reported. The size of the encapsulated dye tunes the mesoporosity and surface area of ZIF-8. The mesopore size, Langmuir surface area and pore volume are 15 nm, 960-1500 m(2). g(-1) and 0.36-0.61 cm(3). g(-1), respectively. After encapsulation into ZIF-8, the dyes show longer emission lifetimes (greater than 4-8-fold) as compared to the corresponding non-encapsulated dyes, due to suppression of aggregation, and torsional motions.

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  • 7.
    Abdelhamid, Hani Nasser
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Assiut University, Egypt; The British University in Egypt (BUE), Egypt.
    Sultan, Sahar
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Mathew, Aji P.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    3D printing of cellulose/leaf-like zeolitic imidazolate frameworks (CelloZIF-L) for adsorption of carbon dioxide (CO2) and heavy metal ions2023In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 52, no 10, p. 2988-2998Article in journal (Refereed)
    Abstract [en]

    Metal–organic frameworks (MOFs) have advanced several technologies. However, it is difficult to market MOFs without processing them into a commercialized structure, causing an unnecessary delay in the material's use. Herein, three-dimensional (3D) printing of cellulose/leaf-like zeolitic imidazolate frameworks (ZIF-L), denoted as CelloZIF-L, is reported via direct ink writing (DIW, robocasting). Formulating CelloZIF-L into 3D objects can dramatically affect the material's properties and, consequently, its adsorption efficiency. The 3D printing process of CelloZIF-L is simple and can be applied via direct printing into a solution of calcium chloride. The synthesis procedure enables the formation of CelloZIF-L with a ZIF content of 84%. 3D printing enables the integration of macroscopic assembly with microscopic properties, i.e., the formation of the hierarchical structure of CelloZIF-L with different shapes, such as cubes and filaments, with 84% loading of ZIF-L. The materials adsorb carbon dioxide (CO2) and heavy metals. 3D CelloZIF-L exhibited a CO2 adsorption capacity of 0.64–1.15 mmol g−1 at 1 bar (0 °C). The materials showed Cu2+ adsorption capacities of 389.8 ± 14–554.8 ± 15 mg g−1. They displayed selectivities of 86.8%, 6.7%, 2.4%, 0.93%, 0.61%, and 0.19% toward Fe3+, Al3+, Co2+, Cu2+, Na+, and Ca2+, respectively. The simple 3D printing procedure and the high adsorption efficiencies reveal the promising potential of our materials for industrial applications.

  • 8.
    Abdelhamid, Hani Nasser
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Assiut University, Egypt; The British University in Egypt, Egypt.
    Sultan, Sahar
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Wallenberg Wood Science Center, Sweden.
    Mathew, Aji P.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Wallenberg Wood Science Center, Sweden.
    Binder-free Three-dimensional (3D) printing of Cellulose-ZIF8 (CelloZIF-8) for water treatment and carbon dioxide (CO2) adsorption2023In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 468, article id 143567Article in journal (Refereed)
    Abstract [en]

    Metal-organic frameworks (MOFs) have advanced several applications, including energy, biomedical and envi-ronmental remediation. However, most of the reported MOF materials are in powder form limiting their ap-plications. This study reported the processing of MOF via three-dimensional (3D) printing of cellulose-MOFs (denoted as CelloMOFs). The 3D printing procedure involved a one-pot method including three steps: gel for-mation, 3D printing, and in-situ growth of MOF crystals. This procedure offered 3D printing of CelloMOF via a binder-free method with high loading of 67.5 wt%. The 3D-printed porous structures were used as adsorbents for carbon dioxide (CO2), dye, and heavy metal ions. They can be also used as catalysts for the degradation of water pollutants such as organic dyes. The materials can be separated easily without requiring extra procedures such as centrifugation or filtration. The materials offered complete (>99%) removal of organic dyes within 10 min with high selectivity toward anionic dyes e.g, methyl blue (MeB). The materials exhibited CO2 and heavy metal ions adsorption capacities of 0.63 mmol/g (27.7 mg/g) and 8-328 mg/g, respectively, with good recyclability. Our methodology will open new venues for advanced 3D printing of CelloMOF and its applications for water treatment and air purification.

  • 9.
    Abdelhamid, Hani Nasser
    et al.
    Stockholm Univ, Dept Mat & Environm Chem, Berzelii Ctr EXSELENT Porous Mat, SE-10691 Stockholm, Sweden;Assiut Univ, Dept Chem, Assiut 71515, Egypt.
    Wilk-Kozubek, Magdalena
    Stockholm Univ, Dept Mat & Environm Chem, Berzelii Ctr EXSELENT Porous Mat, SE-10691 Stockholm, Sweden;PORT Polish Ctr Technol Dev, Dept Nanotechnol, 147 Stablowicka St, PL-54066 Wroclaw, Poland.
    El-Zohry, Ahmed
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Gomez, Antonio Bermejo
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Valiente, Alejandro
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Martin-Matute, Belen
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Mudring, Anja-Verena
    Stockholm Univ, Dept Mat & Environm Chem, Berzelii Ctr EXSELENT Porous Mat, SE-10691 Stockholm, Sweden.
    Zou, Xiaodong
    Stockholm Univ, Dept Mat & Environm Chem, Berzelii Ctr EXSELENT Porous Mat, SE-10691 Stockholm, Sweden.
    Luminescence properties of a family of lanthanide metal-organic frameworks2019In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 279, p. 400-406Article in journal (Refereed)
    Abstract [en]

    Two isostructural series of lanthanide metal-organic frameworks denoted as SUMOF-7II (Ln) and SUMOF-7IIB (Ln) (Ln = La, Ce, Pr, Nd, Sm, Eu, and Gd) were synthesized using4,4',4 ''-(pyridine-2,4,6-triyl)tris(benzoic acid) (H(3)L2) and a mixture of H(3)L2 and 4,4',4 ''-(benzene-1,3,5-triyl)tris(benzoic acid) (H3BTB) as linkers, respectively. Both series were characterized using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermal analysis (TGA), and photoluminescence spectroscopy. Photoluminescence measurements show that Eu-MOFs demonstrate a red emission while Pr- and Nd-MOFs display an emission in the near-infrared (NIR) range. On the other hand, La-, Ce-, Sm- and Gd-MOFs exhibit only a ligand-centered emission. The average luminescence lifetimes in the SUMOF-7IIB series are 1.3-1.4-fold longer than the corresponding ones in the SUMOF-7II series. SUMOF-7IIs show a good photo- and thermal stability. Altogether, the properties of SUMOF-7II and SUMOF-7IIB render them promising materials for applications including sensing, biosensing, and telecommunications.

  • 10.
    Abdelki, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Fused deposition modeling of API-loaded mesoporous magnesium carbonate2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, the incorporation of drug loaded mesoporous magnesium carbonate as an excipient for the additive manufacturing of oral tablets by fused deposition modeling was investigated. Cinnarizine, a BCS class II drug, was loaded into the pores of the mesoporous material via a soaking method, corresponding to a drug loading of 8.68 wt%. DSC measurements on the loaded material suggested that the drug was partially crystallized after incorporation, meanwhile the XRD diffractogram implied that the drug was in a state lacking long range order. The drug loaded material was combined with two pharmaceutical polymers, Aquasolve LG and Klucel ELF, and extruded into filaments with a single screw extruder. Filaments of Klucel ELF and drug loaded Upsalite (30:70 wt% ratio) were successfully implemented for the printing oral tablets, in contrast to the Aquasolve LG based filaments which were difficult to print due to thickness variations and non-uniform material distributions. The drug content obtained by TGA suggested drug loadings of 7.71 wt% and 2.23 wt% in the drug loaded Upsalite and tablets respectively. Dissolution studies using an USP II apparatus showed a slower API-release from the tablets in comparison to the crystalline drug, most probably due to slow diffusion of drug species through the polymeric matrix. For future studies, pharmaceutical polymers with higher aqueous solubility should be investigated in order to thoroughly examine the potential of utilizing the immediate release property of Upsalite.

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  • 11.
    Abdellah, Mohamed
    et al.
    Lund Univ, Div Chem Phys, Box 124, S-22100 Lund, Sweden.;Lund Univ, NanoLund, Box 124, S-22100 Lund, Sweden.;South Valley Univ, Qena Fac Sci, Dept Chem, Qena 83523, Egypt..
    Poulsen, Felipe
    Univ Copenhagen, Dept Chem, DK-2100 Copenhagen, Denmark..
    Zhu, Qiushi
    Lund Univ, Div Chem Phys, Box 124, S-22100 Lund, Sweden.;Lund Univ, NanoLund, Box 124, S-22100 Lund, Sweden..
    Zhu, Nan
    Tech Univ Denmark, Dept Chem, Kemitorvet Bldg 207, DK-2800 Lyngby, Denmark.;Dalian Univ Technol, Zhang Dayu Sch Chem, Dalian 116024, Peoples R China..
    Zidek, Karel
    Acad Sci Czech Republ, Inst Plasma Phys, Reg Ctr Special Opt & Optoelect Syst TOPTEC, Za Slovankou 1782-3, Prague 18200 8, Czech Republic..
    Chabera, Pavel
    Lund Univ, Div Chem Phys, Box 124, S-22100 Lund, Sweden.;Lund Univ, NanoLund, Box 124, S-22100 Lund, Sweden..
    Corti, Annamaria
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hansen, Thorsten
    Univ Copenhagen, Dept Chem, DK-2100 Copenhagen, Denmark..
    Chi, Qijin
    Tech Univ Denmark, Dept Chem, Kemitorvet Bldg 207, DK-2800 Lyngby, Denmark..
    Canton, Sophie E.
    DESY, Attosecond Sci Grp, Notkestr 85, D-22607 Hamburg, Germany.;ELI HU Nonprofit Ltd, ELI ALPS, Dugonics Ter 13, H-6720 Szeged, Hungary..
    Zheng, Kaibo
    Lund Univ, Div Chem Phys, Box 124, S-22100 Lund, Sweden.;Lund Univ, NanoLund, Box 124, S-22100 Lund, Sweden.;Qatar Univ, Coll Engn, Gas Proc Ctr, POB 2713, Doha, Qatar..
    Pullerits, Tonu
    Lund Univ, Div Chem Phys, Box 124, S-22100 Lund, Sweden.;Lund Univ, NanoLund, Box 124, S-22100 Lund, Sweden..
    Drastic difference between hole and electron injection through the gradient shell of CdxSeyZn1−xS1−y quantum dots2017In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 9, no 34, p. 12503-12508Article in journal (Refereed)
    Abstract [en]

    Ultrafast fluorescence spectroscopy was used to investigate the hole injection in CdxSeyZn1-xS1-y gradient core-shell quantum dot (CSQD) sensitized p-type NiO photocathodes. A series of CSQDs with a wide range of shell thicknesses was studied. Complementary photoelectrochemical cell measurements were carried out to confirm that the hole injection from the active core through the gradient shell to NiO takes place. The hole injection from the valence band of the QDs to NiO depends much less on the shell thickness when compared to the corresponding electron injection to n-type semiconductor (ZnO). We simulate the charge carrier tunneling through the potential barrier due to the gradient shell by numerically solving the Schrodinger equation. The details of the band alignment determining the potential barrier are obtained from X-ray spectroscopy measurements. The observed drastic differences between the hole and electron injection are consistent with a model where the hole effective mass decreases, while the gradient shell thickness increases.

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  • 12.
    Abdi, Zahra
    et al.
    Inst Adv Studies Basic Sci IASBS, Dept Chem, Zanjan 4513766731, Iran..
    Bagheri, Robabeh
    Soochow Univ, Sch Phys Sci & Technol, Coll Energy, Soochow Inst Energy & Mat Innovat, Suzhou 215006, Peoples R China.;Soochow Univ, Key Lab Adv Carbon Mat & Wearable Energy Technol, Suzhou 215006, Peoples R China..
    Reza Mohammadi, Mohammad
    Univ Sistan & Baluchestan, Dept Phys, Zahedan 9816745845, Iran..
    Song, Zhenlun
    Chinese Acad Sci, Ningbo Inst Mat Technol & Engn, Surface Dept, Surface Protect Res Grp, 519 Zhuangshi Rd, Ningbo 315201, Peoples R China..
    Görlin, Mikaela
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Dau, Holger
    Free Univ Berlin, Fachbereich Phys, Arnimallee 14, D-14195 Berlin, Germany..
    Najafpour, Mohammad Mahdi
    Inst Adv Studies Basic Sci IASBS, Dept Chem, Zanjan 4513766731, Iran..
    In Situ Synthesis of Manganese Oxide as an Oxygen-Evolving Catalyst: A New Strategy2021In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 27, no 4, p. 1330-1336Article in journal (Refereed)
    Abstract [en]

    All studies on oxygen-evolution reaction by Mn oxides in the presence of cerium(IV) ammonium nitrate (CAN) have been so far carried out by synthesizing Mn oxides in the first step. And then, followed by the investigation of the Mn oxides in the presence of oxidants for oxygen-evolution reaction (OER). This paper presents a case study of a new and promising strategy for in situ catalyst synthesis by the adding Mn-II to either CAN or KMnO4/CAN solution, resulting in the formation of Mn-based catalysts for OER. The catalysts were characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy. Both compounds contained nano-sized particles that catalyzed OER in the presence of CAN. The turnover frequencies for both catalysts were 0.02 (mmolO2 /mol(Mn).

  • 13. Abdi-Jalebi, Mojtaba
    et al.
    Andaji-Garmaroudi, Zahra
    Cacovich, Stefania
    Stavrakas, Camille
    Philippe, Bertrand
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Richter, Johannes M.
    Alsari, Mejd
    Booker, Edward P.
    Hutter, Eline M.
    Pearson, Andrew J.
    Lilliu, Samuele
    Savenije, Tom J.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Divitini, Giorgio
    Ducati, Caterina
    Friend, Richard H.
    Stranks, Samuel D.
    Maximizing and stabilizing luminescence from halide perovskites with potassium passivation2018In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 555, p. 497-501Article in journal (Refereed)
    Abstract [en]

    Metal halide perovskites are of great interest for various high-performance optoelectronic applications. The ability to tune the perovskite bandgap continuously by modifying the chemical composition opens up applications for perovskites as coloured emitters, in building-integrated photovoltaics, and as components of tandem photovoltaics to increase the power conversion efficiency. Nevertheless, performance is limited by non-radiative losses, with luminescence yields in state-of-the-art perovskite solar cells still far from 100 per cent under standard solar illumination conditions. Furthermore, in mixed halide perovskite systems designed for continuous bandgap tunability2 (bandgaps of approximately 1.7 to 1.9 electronvolts), photoinduced ion segregation leads to bandgap instabilities. Here we demonstrate substantial mitigation of both non-radiative losses and photoinduced ion migration in perovskite films and interfaces by decorating the surfaces and grain boundaries with passivating potassium halide layers. We demonstrate external photoluminescence quantum yields of 66 per cent, which translate to internal yields that exceed 95 per cent. The high luminescence yields are achieved while maintaining high mobilities of more than 40 square centimetres per volt per second, providing the elusive combination of both high luminescence and excellent charge transport. When interfaced with electrodes in a solar cell device stack, the external luminescence yield—a quantity that must be maximized to obtain high efficiency—remains as high as 15 per cent, indicating very clean interfaces. We also demonstrate the inhibition of transient photoinduced ion-migration processes across a wide range of mixed halide perovskite bandgaps in materials that exhibit bandgap instabilities when unpassivated. We validate these results in fully operating solar cells. Our work represents an important advance in the construction of tunable metal halide perovskite films and interfaces that can approach the efficiency limits in tandem solar cells, coloured-light-emitting diodes and other optoelectronic applications.

  • 14.
    Abdi-Jalebi, Mojtaba
    et al.
    Univ Cambridge, Dept Phys, Cavendish Lab, JJ Thomson Ave, Cambridge, England.
    Pazoki, Meysam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Philippe, Bertrand
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Dar, M. Ibrahim
    Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photon & Interfaces, Lausanne, Switzerland.
    Alsari, Mejd
    Univ Cambridge, Dept Phys, Cavendish Lab, JJ Thomson Ave, Cambridge, England.
    Sadhanala, Aditya
    Univ Cambridge, Dept Phys, Cavendish Lab, JJ Thomson Ave, Cambridge, England.
    Diyitini, Giorgio
    Univ Cambridge, Dept Mat Sci & Met, Charles Babbage Rd, Cambridge, England.
    Imani, Roghayeh
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Lilliu, Samuele
    Univ Sheffield, Dept Phys & Astron, Sheffield, S Yorkshire, England; UAE Ctr Crystallog, Dubai, U Arab Emirates.
    Kullgren, Jolla
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Gratzel, Michael
    Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photon & Interfaces, Lausanne, Switzerland.
    Friend, Richard H.
    Univ Cambridge, Dept Phys, Cavendish Lab, JJ Thomson Ave, Cambridge, England.
    Dedoping of Lead Halide Perovskites Incorporating Monovalent Cations2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 7, p. 7301-7311Article in journal (Refereed)
    Abstract [en]

    We report significant improvements in the optoelectronic properties of lead halide perovskites with the addition of monovalent ions with ionic radii close to Pb2+. We investigate the chemical distribution and electronic structure of solution processed CH3NH3PbI3 perovskite structures containing Na+, Cu+, and Ag+, which are lower valence metal ions than Pb2+ but have similar ionic radii. Synchrotron X-ray diffraction reveals a pronounced shift in the main perovskite peaks for the monovalent cation-based films, suggesting incorporation of these cations into the perovskite lattice as well as a preferential crystal growth in Ag+ containing perovskite structures. Furthermore, the synchrotron X-ray photoelectron measurements show a significant change in the valence band position for Cu- and Ag-doped films, although the perovskite bandgap remains the same, indicating a shift in the Fermi level position toward the middle of the bandgap. Such a shift infers that incorporation of these monovalent cations dedope the n-type perovskite films when formed without added cations. This dedoping effect leads to cleaner bandgaps as reflected by the lower energetic disorder in the monovalent cation-doped perovskite thin films as compared to pristine films. We also find that in contrast to Ag+ and Cu+, Na+ locates mainly at the grain boundaries and surfaces. Our theoretical calculations confirm the observed shifts in X-ray diffraction peaks and Fermi level as well as absence of intrabandgap states upon energetically favorable doping of perovskite lattice by the monovalent cations. We also model a significant change in the local structure, chemical bonding of metal-halide, and the electronic structure in the doped perovskites. In summary, our work highlights the local chemistry and influence of monovalent cation dopants on crystallization and the electronic structure in the doped perovskite thin films.

  • 15. Abdin, Amir
    et al.
    Feyzabi, Kaveh
    Hellman, Oskar
    Nordström, Henrietta
    Rasa, Dilman
    Thaung Tolförs, Gustav
    Öqvist, Per-Olof
    Methods to create compressive stress in high strength steel components2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Residual compressive stresses can be used to increase the lifetime of parts under cyclic stress as they negate the applied tensile stresses that cause crack initiation and propagation in the material. The goal of this project was to investigate methods to induce stresses, their advantages and disadvantages as well as depth and magnitude of induced stresses, and also to find methods of analyzing the induced residual stresses. This was done on behalf of Epiroc Drilling Tools AB in order for them to induce stresses on the insides of their long, narrow and hollow rods, where stress induction is difficult. Shot peening was used as a reference as that is the method currently in use by the company. The results show that the two most promising methods are cavitation peening and laser shock peening; two relatively new methods with large magnitudes and depth of induced stress as well as a great capability of inducing stresses on the hard-to-reach insides of the rods. Ultrasonic needle peening, ultrasonic shot peening as well as induction hardening, cryogenic treatment and friction stir processing were also investigated. Methods of analyzing the stresses include X-ray diffraction and slitting, hole drilling and ultrasonic methods.

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  • 16.
    Abdulla, Beyar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Nanocellulose surface functionalization for in-situ growth of zeolitic imidazolate framework 67 and 82020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master’s thesis was conducted at the Department of Nanotechnology and Functional Materials at Ångström Laboratory as part of an on-going project to develop hybrid nanocomposites from Cladophora cellulose and a sub-type of metal-organic frameworks; zeolitic imidazolate frameworks (ZIFs). By utilizing a state-of-the-art interfacial synthesis approach, in-situ growth of ZIF particles on the cellulose could be achieved. TEMPO-mediated oxidation was diligently used to achieve cellulose nanofibers with carboxylate groups on their surfaces. These were ion-exchanged to promote growth of ZIF particles in a nanocellulose solution and lastly, metal ions and organic linkers which the ZIFs are composed of were added to the surface functionalized and ion-exchanged nanocellulose solution to promote ZIF growth. By vacuum filtration, mechanical pressing and furnace drying; freestanding nanopapers were obtained. A core-shell morphology between the nanocellulose and ZIF crystals was desired and by adjusting the metal ion concentration, a change in morphologies was expected. The nanocomposites were investigated with several relevant analytical tools to confirm presence, attachment and in-situ growth of ZIF crystal particles upon the surface of the fine nanocellulose fibers. Both the CNF@ZIF-67 and CNF@ZIF-8 nanocomposites were successfully prepared as nanopapers with superior surface areas and thermal properties compared to pure TEMPO-oxidized cellulose nanopapers. The CNF@ZIFs showcased hierarchical porosities, stemming from the micro- and mesoporous ZIFs and nanocellulose, respectively. Also, it was demonstrated that CNF@ZIF-8 selectively adsorbed CO2 over N2. Partial formation of core-shell structure could be obtained, although a relationship between increased metal ions and ZIF particle morphology could not wholly be observed.

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  • 17.
    Abedin, Ahmad
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Zurauskaite, Laura
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Asadollahi, Ali
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Garidis, Konstantinos
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Jayakumar, Ganesh
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Malm, B. Gunnar
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Hellström, Per-Erik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Östling, Mikael
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Germanium on Insulator Fabrication for Monolithic 3-D Integration2018In: IEEE Journal of the Electron Devices Society, E-ISSN 2168-6734, Vol. 6, no 1, p. 588-593Article in journal (Refereed)
    Abstract [en]

    A low temperature (T-max = 350 degrees C) process for Germanium (Ge) on insulator (GOI) substrate fabrication with thicknesses of less than 25 nm is reported in this paper. The process is based on a single step epitaxial growth of a Ge/SiGe/Ge stack on Si, room temperature wafer bonding and an etch-back process using Si0.5Ge0.5 as an etch-stop layer. GOI substrates with surface roughness below 0.5 nm, 0.15% tensile strain, thickness nonuniformity of less than 3 nm and residual p-type doping of less than 1016 cm(-3) were fabricated. Ge pFETs are fabricated (T-max = 600 degrees C) on the GOI wafer with 70% yield. The devices exhibit a negative threshold voltage of -0.18 V and 60% higher mobility than the SOI pFET reference devices.

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  • 18.
    Aboulfadl, Hisham
    et al.
    Chalmers Univ Technol, Dept Phys, Div Microstruct Phys, S-41296 Gothenburg, Sweden..
    Sopiha, Kostiantyn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Keller, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Larsen, Jes K
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Scragg, Jonathan J.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Persson, Clas
    Univ Oslo, Ctr Mat Sci & Nanotechnol, Dept Phys, N-0316 Oslo, Norway.;KTH Royal Inst Technol, Dept Mat Sci & Engn, Div Appl Mat Phys, S-10044 Stockholm, Sweden..
    Thuvander, Mattias
    Chalmers Univ Technol, Dept Phys, Div Microstruct Phys, S-41296 Gothenburg, Sweden..
    Edoff, Marika
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Alkali Dispersion in (Ag,Cu)(In,Ga)Se-2 Thin Film Solar Cells-Insight from Theory and Experiment2021In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 13, no 6, p. 7188-7199Article in journal (Refereed)
    Abstract [en]

    Silver alloying of Cu(In,Ga)Se-2 absorbers for thin film photovoltaics offers improvements in open-circuit voltage, especially when combined with optimal alkali-treatments and certain Ga concentrations. The relationship between alkali distribution in the absorber and Ag alloying is investigated here, combining experimental and theoretical studies. Atom probe tomography analysis is implemented to quantify the local composition in grain interiors and at grain boundaries. The Na concentration in the bulk increases up to similar to 60 ppm for [Ag]/([Ag] + [Cu]) = 0.2 compared to similar to 20 ppm for films without Ag and up to similar to 200 ppm for [Ag]/([Ag] + [Cu]) = 1.0. First-principles calculations were employed to evaluate the formation energies of alkali-on-group-I defects (where group-I refers to Ag and Cu) in (Ag,Cu)(In,Ga)Se-2 as a function of the Ag and Ga contents. The computational results demonstrate strong agreement with the nanoscale analysis results, revealing a clear trend of increased alkali bulk solubility with the Ag concentration. The present study, therefore, provides a more nuanced understanding of the role of Ag in the enhanced performance of the respective photovoltaic devices.

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  • 19.
    Abrahamsson, Tobias
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Poxson, David
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gabrielsson, Erik
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Sandberg, Mats
    RISE Acreo AB, Sweden.
    Simon, Daniel T
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol2019In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, article id 484Article in journal (Refereed)
    Abstract [en]

    In the emerging field of organic bioelectronics, conducting polymers and ion-selective membranes are combined to form resistors, diodes, transistors, and circuits that transport and process both electronic and ionic signals. Such bioelectronics concepts have been explored in delivery devices that translate electronic addressing signals into the transport and dispensing of small charged biomolecules at high specificity and spatiotemporal resolution. Manufacturing such "iontronic" devices generally involves classical thin film processing of polyelectrolyte layers and insulators followed by application of electrolytes. This approach makes miniaturization and integration difficult, simply because the ion selective polyelectrolytes swell after completing the manufacturing. To advance such bioelectronics/iontronics and to enable applications where relatively larger molecules can be delivered, it is important to develop a versatile material system in which the charge/size selectivity can be easily tailormade at the same time enabling easy manufacturing of complex and miniaturized structures. Here, we report a one-pot synthesis approach with minimal amount of organic solvent to achieve cationic hyperbranched polyglycerol films for iontronics applications. The hyperbranched structure allows for tunable pre multi-functionalization, which combines available unsaturated groups used in crosslinking along with ionic groups for electrolytic properties, to achieve a one-step process when applied in devices for monolithic membrane gel formation with selective electrophoretic transport of molecules.

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  • 20.
    Abrashev, Miroslav V.
    et al.
    Univ Sofia St Kliment Ohridski, Fac Phys, Sofia 1164, Bulgaria.
    Chernev, Petko
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. Free Univ Berlin, Fachbereich Phys, Arnimallee 14, D-14195 Berlin, Germany.
    Kubella, Paul
    Free Univ Berlin, Fachbereich Phys, Arnimallee 14, D-14195 Berlin, Germany.
    Mohammadi, Mohammad Reza
    Free Univ Berlin, Fachbereich Phys, Arnimallee 14, D-14195 Berlin, Germany;Univ Sistan & Baluchestan, Dept Phys, Zahedan 9816745845, Iran.
    Pasquini, Chiara
    Free Univ Berlin, Fachbereich Phys, Arnimallee 14, D-14195 Berlin, Germany.
    Dau, Holger
    Free Univ Berlin, Fachbereich Phys, Arnimallee 14, D-14195 Berlin, Germany.
    Zaharieva, Ivelina
    Free Univ Berlin, Fachbereich Phys, Arnimallee 14, D-14195 Berlin, Germany.
    Origin of the heat-induced improvement of catalytic activity and stability of MnOx electrocatalysts for water oxidation2019In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 28, p. 17022-17036Article in journal (Refereed)
    Abstract [en]

    Catalysis of the oxygen evolution reaction (OER) by earth-abundant materials in the near-neutral pH regime is of great interest as it is the key reaction for non-fossil fuel production. To address the pertinent stability problems and insufficiently understood structure-activity relations, we investigate the influence of moderate annealing (100-300 degrees C for 20 min) for two types of electrodeposited Mn oxide films with contrasting properties. Upon annealing, the originally inactive and structurally well-ordered Oxide 1 of birnessite type became as OER active as the non-heated Oxide 2, which has a highly disordered atomic structure. Oxide 2 also improved its activity upon heating, but more important is the stability improvement: the operation time increased by about two orders of magnitude (in 0.1 M KPi at pH 7). Aiming at atomistic understanding, electrochemical methods including quantitative analysis of impedance spectra, X-ray spectroscopy (XANES and EXAFS), and adapted optical spectroscopies (infrared, UV-vis and Raman) identified structure-reactivity relations. Oxide structures featuring both di-mu-oxo bridged Mn ions and (close to) linear mono-mu-oxo Mn3+-O-Mn4+ connectivity seem to be a prerequisite for OER activity. The latter motif likely stabilizes Mn3+ ions at higher potentials and promotes electron/hole hopping, a feature related to electrical conductivity and reflected in the strongly accelerated rates of Mn oxidation and O-2 formation. Poor charge mobility, which may result from a low level of Mn3+ ions at high potentials, likely promotes inactivation after prolonged operation. Oxide structures related to the perovskite-like zeta-Mn2O3 were formed after the heating of Oxide 2 and could favour stabilization of Mn ions in oxidation states lower than +4. This rare phase was previously found only at high pressure (20 GPa) and temperature (1200 degrees C) and this is the first report where it was stable under ambient conditions.

  • 21.
    Abrikossova, Natalia
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Investigation of nanoparticle-cell interactions for development of next generation of biocompatible MRI contrast agents2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Progress in synthesis technologies and advances in fundamental understanding of materials with low dimensionality has led to the birth of a new scientific field, nanoscience, and to strong expectations of multiple applications of nanomaterials. The physical properties of small particles are unique, bridging the gap between atoms and molecules, on one side, and bulk materials on the other side. The work presented in this thesis investigates the potential of using magnetic nanoparticles as the next generation of contrast agents for biomedical imaging. The focus is on gadolinium-based nanoparticles and cellular activity including the uptake, morphology and production of reactive oxygen species.

    Gd ion complexes, like Gd chelates, are used today in the clinic, world-wide. However, there is a need for novel agents, with improved contrast capabilities and increased biocompatibility. One avenue in their design is based on crystalline nanoparticles. It allows to reduce the total number of Gd ions needed for an examination. This can be done by nanotechnology, which allows one to improve and fine tune the physico- chemical properties on the nanomaterial in use, and to increase the number of Gd atoms at a specific site that interact with protons and thereby locally increase the signal. In the present work, synthesis, purification and surface modification of crystalline Gd2O3-based nanoparticles have been performed. The nanoparticles are selected on the basis of their physical properties, that is they show enhanced magnetic properties and therefore may be of high potential interest for applications as contrast agents.

    The main synthesis method of Gd2O3 nanoparticles in this work was the modified “polyol” route, followed by purification of as-synthesized DEG-Gd2O3 nanoparticles suspensions. In most cases the purification step involved dialysis of the nanoparticle samples. In this thesis, organosilane were chosen as an exchange agent for further functionalization. Moreover, several paths have been explored for modification of the nanoparticles, including Tb3+ doping and capping with sorbitol.

    Biocompatibility of the newly designed nanoparticles is a prerequisite for their use in medical applications. Its evaluation is a complex process involving a wide range of biological phenomena. A promising path adopted in this work is to study of nanoparticle interactions with isolated blood cells. In this way one could screen nanomaterial prior to animal studies.

    The primary cell type considered in the thesis are polymorphonuclear neutrophils (PMN) which represent a type of the cells of human blood belonging to the granulocyte family of leukocytes. PMNs act as the first defense of the immune system against invading pathogens, which makes them valuable for studies of biocompatibility of newly synthesized nanoparticles. In addition, an immortalized murine alveolar macrophage cell line (MH-S), THP-1 cell line, and Ba/F3 murine bone marrow-derived cell line were considered to investigate the optimization of the cell uptake and to examine the potential of new intracellular contrast agent for magnetic resonance imaging.

    In paper I, the nanoparticles were investigated in a cellular system, as potential probes for visualization and targeting intended for bioimaging applications. The production of reactive oxygen species (ROS) by means of luminol-dependent chemiluminescence from human neutrophils was studied in presence of Gd2O3 nanoparticles. In paper II, a new design of functionalized ultra-small rare earth-based nanoparticles was reported. The synthesis was done using polyol method followed by PEGylation, and dialysis. Supersmall gadolinium oxide (DEG-Gd2O3) nanoparticles, in the range of 3-5 nm were obtained and carefully characterized. Neutrophil activation after exposure to this nanomaterial was studied by means of fluorescence microscopy. In paper III, cell labeling with Gd2O3 nanoparticles in hematopoietic cells was monitored by magnetic resonance imaging (MRI). In paper IV, ultra-small gadolinium oxide nanoparticles doped with terbium ions were synthesized as a potentially bifunctional material with both fluorescent and magnetic contrast agent properties. Paramagnetic behavior was studied. MRI contrast enhancement was received, and the luminescent/ fluorescent property of the particles was attributable to the Tb3+ ion located on the crystal lattice of the Gd2O3 host. Fluorescent labeling of living cells was obtained. In manuscript V, neutrophil granulocytes were investigated with rapid cell signaling communicative processes in time frame of minutes, and their response to cerium-oxide based nanoparticles were monitored using capacitive sensors based on Lab-on-a-chip technology. This showed the potential of label free method used to measure oxidative stress of neutrophil granulocytes. In manuscript VI, investigations of cell-(DEGGd2O3) nanoparticle interactions were carried out. Plain (DEG-Gd2O3) nanoparticles, (DEG-Gd2O3) nanoparticles in presence of sorbitol and (DEG-Gd2O3) nanoparticles capped with sorbitol were studied. Relaxation studies and measurements of the reactive oxygen species production by neutrophils were based on chemiluminescence. Cell morphology was evaluated as a parameter of the nanoparticle induced inflammatory response by means of the fluorescence microscopy.

    The thesis demonstrates high potential of novel Gd2O3-based nanoparticles for development of the next generation contrast agents, that is to find biocompatible compounds with high relaxivity that can be detected at lower doses, and in the future enable targeting to provide great local contrast.

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  • 22.
    Abrikossova, Natalia
    et al.
    Division of Molecular Surface Physics and Nanoscience, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden .
    Skoglund, Caroline
    Division of Molecular Surface Physics and Nanoscience, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden; Division of Clinical Medicine, Department of Biomedicine, Örebro University, Örebro, Sweden.
    Ahrén, Maria
    Division of Molecular Surface Physics and Nanoscience, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.
    Bengtsson, Torbjörn
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Division of Clinical Medicine, Department of Biomedicine, School of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Uvdal, Kajsa
    Division of Molecular Surface Physics and Nanoscience, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.
    Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes2012In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 23, no 27, article id 275101Article in journal (Refereed)
    Abstract [en]

    We have previously shown that gadolinium oxide (Gd2O3) nanoparticles are promising candidates to be used as contrast agents in magnetic resonance (MR) imaging applications. In this study, these nanoparticles were investigated in a cellular system, as possible probes for visualization and targeting intended for bioimaging applications. We evaluated the impact of the presence of Gd2O3 nanoparticles on the production of reactive oxygen species (ROS) from human neutrophils, by means of luminol-dependent chemiluminescence. Three sets of Gd2O3 nanoparticles were studied, i.e. as synthesized, dialyzed and both PEG-functionalized and dialyzed Gd2O3 nanoparticles. In addition, neutrophil morphology was evaluated by fluorescent staining of the actin cytoskeleton and fluorescence microscopy. We show that surface modification of these nanoparticles with polyethylene glycol (PEG) is essential in order to increase their biocompatibility. We observed that the as synthesized nanoparticles markedly decreased the ROS production from neutrophils challenged with prey (opsonized yeast particles) compared to controls without nanoparticles. After functionalization and dialysis, more moderate inhibitory effects were observed at a corresponding concentration of gadolinium. At lower gadolinium concentration the response was similar to that of the control cells. We suggest that the diethylene glycol (DEG) present in the as synthesized nanoparticle preparation is responsible for the inhibitory effects on the neutrophil oxidative burst. Indeed, in the present study we also show that even a low concentration of DEG, 0.3%, severely inhibits neutrophil function. In summary, the low cellular response upon PEG-functionalized Gd2O3 nanoparticle exposure indicates that these nanoparticles are promising candidates for MR-imaging purposes.

  • 23.
    Abutalib, M. M.
    et al.
    Univ Jeddah, Saudi Arabia.
    Alghamdi, Haifa Mohammed
    Univ Jeddah, Saudi Arabia.
    Rajeh, A.
    Amran Univ, Yemen.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Hezma, A. M.
    Natl Res Ctr, Egypt.
    Mannaa, Mohammed A.
    Amran Univ, Yemen.
    Fe3O4/Co3O4-TiO2 S-scheme photocatalyst for degradation of organic pollutants and H-2 production under natural sunlight2022In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 20, p. 1043-1056Article in journal (Refereed)
    Abstract [en]

    Sunlight responsible mono-and co-doped TiO2 nanoparticles (Con+ and Fen+) were prepared via sol-gel technique. The X-ray diffraction (XRD) results showed no phase change of TiO2 was observed after the addition of Con+ and Fen+ ions. Diffuse reflectance spectra (DRS) results showed a significant red-shift of the absorption edge after doping TiO2 by Co(n )and Fen+ and the band gap energy reduced sharply from 3.10 to 1.72 eV. X-ray photoelectron spectroscopy (XPS) results emphasized the existence of multivalent states of Co2+, Co3+, Fe2+ and Fe3+. The results of ultraviolet photoelectron spectroscopy (UPS), work function, electron spin resonance (ESR) illustrated the Fe3O4/Co3O4-TiO2 formed of ternary hetero-junctions. The photocatalytic performance of the prepared photocatalysts was determined for photodegradation of tetracycline (TC) and phenol (Pl) and production of hydrogen. The results illustrated the existence of multivalent states of Fe and Co ions (Co2+, Co3+, Fe2+ and Fe3+) together improved the solar light absorption, inhibited the recombination of photo -generated charges and consequently enhanced the photocatalytic efficiency of TiO2 compared with mono-doped TiO2 (Co3O4/TiO2 and Fe3O4/TiO2). The sample with 5%Fe3O4/ Co(3)O(4)4-TiO2 showed the highest photoactivity. The mineralization (TOC), photodegradation mechanism and reusability of prepared photocatalysts were also studied. The Fe3O4/Co3O4-TiO2 nanoparticles showed high photoactivity and stability and can be adopted as a promising materials for different environmental and H-2 production applications. (C) 2022 The Author(s). Published by Elsevier B.V.

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  • 24.
    Abutalib, M. M.
    et al.
    Univ Jeddah, Saudi Arabia.
    Alghamdi, Haifa Mohammed
    Univ Jeddah, Saudi Arabia.
    Rajeh, A.
    Amran Univ, Yemen.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Hezmad, A. M.
    Natl Res Ctr, Egypt.
    Mannaa, Mohammed A.
    Amran Univ, Yemen.
    Preparation of rGO/FeMoO4 as high-performance photocatalyst for degradation of malachite green, phenol and H2 evolution under natural sunlight2022In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 47, no 77, p. 32955-32968Article in journal (Refereed)
    Abstract [en]

    FeMoO4 and rGO/FeMoO4 nanocomposites were successfully prepared by a facile hydro-thermal method. The XRD results confirmed that the FeMoO4 has a monometallic b-FeMoO4 crystalline phase while the rGO/FeMoO4 showed both monometallic a-and b-FeMoO4 phases where b-FeMoO4 is the predominant phase. The reduction of graphene oxide (GO) to reduced graphene oxide (rGO) was performed without using any chemical reductions. UV-Vis results showed that the visible light absorption and band gap energy were enhanced after the addition of rGO. The prepared samples were successfully applied for degradation of malachite green (MG) and phenol (Ph) and for H2 evolution under natural solar light irradiation. All the nanocomposites showed higher photocatalytic activities compared with pure FeMoO4 photocatalyst, and the 10%rGO/FeMoO4 gave the highest photodegradation performance for MG and Ph and for H2 evolution. The photodegradation results revealed that the rGO content played the crucial factor in the photodegradation of MG and Ph, and H2 evolution. The mineralization (TOC), photodegradation mechanism and degradation kinetics of MG and Ph were discussed.

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  • 25. Acharya, Shravan S.
    et al.
    Easton, Christopher D.
    McCoy, Thomas M.
    Spiccia, Leone
    Ohlin, C. André
    Umeå University, Faculty of Science and Technology, Department of Chemistry. School of Chemistry, Monash University, Clayton, Australia.
    Winther-Jensen, Bjorn
    Diverse composites of metal-complexes and PEDOT facilitated by metal-free vapour phase polymerization2017In: Reactive & functional polymers, ISSN 1381-5148, E-ISSN 1873-166X, Vol. 116, p. 101-106Article in journal (Refereed)
    Abstract [en]

    Abstract Oxidative polymerization for the manufacture of conducting polymers such as poly(3,4-ethylenedioxy-thiophene) has traditionally employed iron(III) salts. Demonstrated in this study is vapour phase polymerization of 3,4-ethylenedio- xythiophene using a metal-free oxidant, ammonium persulfate, leading to films with an estimated conductivity of 75 S/cm. Additionally, a route for embedding active transition metal complexes into these poly(3,4-ethylenedioxythiophene)/-poly(styrene-4-sulfonate) (PEDOT/PSS) films via vapour assisted complexation is outlined. Here, the vapour pressure of solid ligands around their melting temperatures was exploited to ensure complexation to metal ions added into the oxidant mixture prior to polymerization of PEDOT. Four composite systems are discussed, viz. PEDOT/PSS embedded with tris(8-hydroxyquinolinato)cobalt(III), tris(2,2-bipyridine)cobalt(II), tris(1,10- phenanthroline)cobalt(II) and tris(8-hyd-roxyquinolinato)aluminium(III). Using these composites, electrochemical reduction of nitrite to ammonia with a faradaic efficiency of 61% was reported.

  • 26.
    Achenbach, Jan-Ole
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Karimi Aghda, Soheil
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Hans, Marcus
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Holzapfel, Damian M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Miljanovic, Danilo J.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Low temperature oxidation behavior of Mo2BC coatings2020In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 38, no 2, article id 023403Article in journal (Refereed)
    Abstract [en]

    Mo2BC exhibits a unique combination of high stiffness and moderate ductility, enabling the application as a protective and wear resistant coating. As the low temperature oxidation behavior of Mo2BC coatings is unexplored, direct current magnetron sputtered Mo2BC coatings were oxidized at temperatures ranging from 500 to 100 degrees C for up to 28 days. Time-of-flight elastic recoil detection analysis reveals that the onset of oxidation takes place at approximately 300 degrees C as a significant increase in the O content was observed. Crystalline oxide scales containing orthorhombic MoO3 were identified after oxidation for 15 min at 500 degrees C and 10 days at 200 degrees C. Isothermal oxidation at 200 and 100 degrees C exhibits oxide scale thicknesses of 401 +/- 33 and 22 +/- 10 nm after 14 days. Oxidation for 28 days at 100 degrees C exhibits an oxide scale thickness of 13 +/- 3 nm, which is comparable to the aforementioned oxide scale thickness after oxidation for 14 days at 100 degrees C. Based on the combination of mechanical properties and the here reported low temperature oxidation behavior, Mo2BC coatings qualify for applications in solid wood machining and low temperature forming processes at temperatures close to 100 degrees C or below.

  • 27.
    Achenbach, Jan-Ole
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Sahu, Rajib
    Max Planck Inst Eisenforsch GmbH, Max Planck Str 1, D-40237 Dusseldorf, Germany.
    Voelker, Bernhard
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany;Max Planck Inst Eisenforsch GmbH, Max Planck Str 1, D-40237 Dusseldorf, Germany.
    Hans, Marcus
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Miljanovic, Danilo J.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Scheu, Christina
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany;Max Planck Inst Eisenforsch GmbH, Max Planck Str 1, D-40237 Dusseldorf, Germany.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany;Max Planck Inst Eisenforsch GmbH, Max Planck Str 1, D-40237 Dusseldorf, Germany.
    Synthesis and Properties of Orthorhombic MoAlB Coatings2019In: Coatings, ISSN 2079-6412, Vol. 9, no 8, article id 510Article in journal (Refereed)
    Abstract [en]

    MoAlB is a potential candidate for high-temperature application since a dense, adherent alumina scale is formed. While, based on X-ray diffraction investigations, the formation of phase pure orthorhombic MoAlB coatings is observed, energy dispersive X-ray spectroscopy carried out in a scanning transmission electron microscope reveals the presence of Al-rich and O-rich regions within the MoAlB matrix. The oxidation kinetics of coatings and bulk is similar to the scale thickness formed on the MoAlB coating after oxidation at 1200 degrees C for 30 min is similar to the one extrapolated for bulk MoAlB. Furthermore, the oxidation kinetics of MoAlB coatings is significantly lower than the one reported for bulk Ti2AlC. Finally, the elastic properties measured for the as-deposited coatings are consistent ab initio predictions.

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  • 28. Acker, Pascal
    et al.
    Rzesny, Luisa
    Marchiori, Cleber F. N.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Araujo, Carlos Moyses
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Esser, Birgit
    π-Conjugation Enables Ultra-High Rate Capabilities and Cycling Stabilities in Phenothiazine Copolymers as Cathode-Active Battery Materials2019In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 29, no 45, article id 1906436Article in journal (Refereed)
    Abstract [en]

    In recent years, organic battery cathode materials have emerged as an attractive alternative to metal oxide–based cathodes. Organic redox polymers that can be reversibly oxidized are particularly promising. A drawback, however, often is their limited cycling stability and rate performance in a high voltage range of more than 3.4 V versus Li/Li+. Herein, a conjugated copolymer design with phenothiazine as a redox‐active group and a bithiophene co‐monomer is presented, enabling ultra‐high rate capability and cycling stability. After 30 000 cycles at a 100C rate, >97% of the initial capacity is retained. The composite electrodes feature defined discharge potentials at 3.6 V versus Li/Li+ due to the presence of separated phenothiazine redox centers. The semiconducting nature of the polymer allows for fast charge transport in the composite electrode at a high mass loading of 60 wt%. A comparison with three structurally related polymers demonstrates that changing the size, amount, or nature of the side groups leads to a reduced cell performance. This conjugated copolymer design can be used in the development of advanced redox polymers for batteries.

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  • 29.
    Acker, Pascal
    et al.
    University of Freiburg, Germany.
    Rzesny, Luisa
    University of Freiburg, Germany.
    Marchiori, Cleber F. N.
    Uppsala universitet.
    Araujo, Carlos Moyses
    Uppsala universitet.
    Esser, Birgit
    University of Freiburg, Germany.
    π-Conjugation Enables Ultra-High Rate Capabilities and Cycling Stabilities in Phenothiazine Copolymers as Cathode-Active Battery Materials2019In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 29, no 45, article id 1906436Article in journal (Refereed)
    Abstract [en]

    In recent years, organic battery cathode materials have emerged as an attractive alternative to metal oxide–based cathodes. Organic redox polymers that can be reversibly oxidized are particularly promising. A drawback, however, often is their limited cycling stability and rate performance in a high voltage range of more than 3.4 V versus Li/Li+. Herein, a conjugated copolymer design with phenothiazine as a redox‐active group and a bithiophene co‐monomer is presented, enabling ultra‐high rate capability and cycling stability. After 30 000 cycles at a 100C rate, >97% of the initial capacity is retained. The composite electrodes feature defined discharge potentials at 3.6 V versus Li/Li+ due to the presence of separated phenothiazine redox centers. The semiconducting nature of the polymer allows for fast charge transport in the composite electrode at a high mass loading of 60 wt%. A comparison with three structurally related polymers demonstrates that changing the size, amount, or nature of the side groups leads to a reduced cell performance. This conjugated copolymer design can be used in the development of advanced redox polymers for batteries.

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  • 30.
    Adalsteinsson, Alfred
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Reactions of Li-metal electrodes in contact with electrolytes, characterized by surface analysis techniques2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
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  • 31.
    Adalsteinsson, Sigurbjörn Már
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Moro, Marcos V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Moldarev, Dmitrii
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics. Moscow Engn Phys Inst, Dept Mat Sci, Moscow 115409S, Russia..
    Droulias, Sotiris
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Wolff, Max
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics. Moscow Engn Phys Inst, Dept Mat Sci, Moscow 115409S, Russia..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Sweden.;Uppsala Univ, Tandem Lab, Box 529, S-75120 Uppsala, Sweden..
    Correlating chemical composition and optical properties of photochromic rare-earth oxyhydrides using ion beam analysis2020In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 485, p. 36-40Article in journal (Refereed)
    Abstract [en]

    We relate the photochromic response of rare-earth oxyhydride thin films (YHO, NdHO, GdHO and DyHO) synthesized by reactive magnetron sputtering to chemical composition. Depth profiles of the sample composition are extracted by a multi-method ion beam analysis approach. The total areal density of the thin films is deduced from Rutherford Backscattering Spectrometry while coincidence Time-of-Flight/Energy Elastic Recoil Detection Analysis provides depth-profiles of the film constituents. High-resolution depth profiles of the concentration of light species, i.e. hydrogen and oxygen, are additionally extracted from Nuclear Reaction Analysis and Elastic Backscattering Spectrometry, respectively. The photochromic response of the films is measured by optical transmission spectroscopy before and after illumination. We report photochromic properties for YHO, NdHO, GdHO and DyHO for chemical compositions described by the formula REH2-delta O delta in the range of 0.45 < 6 < 1.5.

  • 32.
    Adam, Rania E.
    et al.
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Chalangar, Ebrahim
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS). Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Pirhashemi, Mahsa
    Department of Chemistry, Faculty of Sciences, University of Mohaghegh Ardabili, Ardabil, Iran.
    Pozina, Galia
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Liu, Xianjie
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Palisaitis, Justinas
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Department of Sciences and Technology, Linköping University, Norrköping, Sweden & Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Willander, Magnus
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Nur, Omer
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities2019In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 52, p. 30585-30598Article in journal (Refereed)
    Abstract [en]

    High-efficiency photocatalysts are crucial for the removal of organic pollutants and environmental sustainability. In the present work, we report on a new low-temperature hydrothermal chemical method, assisted by ultrasonication, to synthesize disruptive plasmonic ZnO/graphene/Ag/AgI nanocomposites for solar-driven photocatalysis. The plasmonic nanocomposites were investigated by a wide range of characterization techniques, confirming successful formation of photocatalysts with excellent degradation efficiency. Using Congo red as a model dye molecule, our experimental results demonstrated a photocatalytic reactivity exceeding 90% efficiency after one hour simulated solar irradiation. The significantly enhanced degradation efficiency is attributed to improved electronic properties of the nanocomposites by hybridization of the graphene and to the addition of Ag/AgI which generates a strong surface plasmon resonance effect in the metallic silver further improving the photocatalytic activity and stability under solar irradiation. Scavenger experiments suggest that superoxide and hydroxyl radicals are responsible for the photodegradation of Congo red. Our findings are important for the fundamental understanding of the photocatalytic mechanism of ZnO/graphene/Ag/AgI nanocomposites and can lead to further development of novel efficient photocatalyst materials. © 2019 Elsevier B.V.

  • 33.
    Adam, Rania Elhadi
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Synthesis and Characterization of Some Nanostructured Materials for Visible Light-driven Photo Processes2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nanostructured materials for visible light driven photo-processes such as photodegradation of organic pollutants and photoelectrochemical (PEC) water oxidation for hydrogen production are very attractive because of the positive impact on the environment. Metal oxides-based nanostructures are widely used in these photoprocesses due to their unique properties. But single nanostructured metal oxide material might suffer from low efficiency and instability in aqueous solutions under visible light. These facts make it important to have an efficient and reliable nanocomposite for the photo-processes. The combination of different nanomaterials to form a composite configuration can produce a material with new properties. The new properties which are due to the synergetic effect, are a combination of the properties of all the counterparts of the nanocomposite. Zinc oxides (ZnO) have unique optical and electrical properties which grant it to be used in optoelectronics, sensors, solar cells, nanogenerators, and photocatalysis activities. Although ZnO absorbs visible light from the sun due to the deep level band, it mainly absorbs ultraviolet wavelengths which constitute a small portion of the whole solar spectrum range. Also, ZnO has a problem with the high recombination rate of the photogenerated electrons. These problems might reduce its applicability to the photo-process. Therefore, our aim is to develop and investigate different nanocomposites materials based on the ZnO nanostructures for the enhancement of photocatalysis processes using the visible solar light as a green source of energy. Two photo-processes were applied to examine the developed nanocomposites through photocatalysis: (1) the photodegradation of organic dyes, (2) PEC water splitting. In the first photo-process, we used the ZnO nanoparticles (NPs), Magnesium (Mg)-doped ZnO NPs, and plasmonic ZnO/graphene-based nanocomposite for the decomposition of some organic dyes that have been used in industries. For the second photo-process, ZnO photoelectrode composite with different silver-based semiconductors to enhance the performance of the ZnO photoelectrode was used for PEC reaction analysis to perform water splitting. The characterization and photocatalysis experiment results showed remarkable enhancement in the photocatalysis efficiency of the synthesized nanocomposites. The observed improved properties of the ZnO are due to the synergetic effects are caused by the addition of the other nanomaterials. Hence, the present thesis attends to the synthesis and characterization of some nanostructured materials composite with ZnO that are promising candidates for visible light-driven photo-processes.  

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  • 34.
    Adam, Rania Elhadi
    et al.
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics.
    Nur, Omer
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics.
    Synthesis of Mg-doped ZnO NPs via a chemical low-temperature method and investigation of the efficient photocatalytic activity for the degradation of dyes under solar light2020In: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 99, article id 106053Article in journal (Refereed)
    Abstract [en]

    Doped semiconductors nanostructures (NSs) have shown great interest as a potential for green and efficient photocatalysis activities. Magnesium (Mg)-doped zinc oxide (ZnO) nanoparticles (NPs) has been synthesized by a one-step chemical low temperature (60 °C) co-precipitation method without further calcination and their photocatalytic performance for photodegradation of Methylene blue (MB) dye under the illumination of solar light is investigated. The crystal structure of the synthesized NPs is examined by X-ray diffraction (XRD). XRD data indicates a slight shift towards higher 2θ angle in Mg-doped samples as compared to the pure ZnO NPs which suggest the incorporation of Mg2+ into ZnO crystal lattice. X-ray photoelectron spectroscopy (XPS), UV–Vis spectrophotometer and cathodoluminescence (CL) spectroscopy, were used to study electronics, and optical properties, respectively. The XPS analysis confirms the substitution of the Zn2+ by the Mg2+ into the ZnO crystal lattice in agreement with the XRD data. The photocatalytic activities showed a significant enhancement of the Mg-doped ZnO NPs in comparison with pure ZnO NPs. Hole/radical scavengers were used to reveal the mechanism of the photodegradation. It was found that the addition of the Mg to the ZnO lattices increases the absorption of the hydroxyl ions at the surface of the NPs and hence acts as a trap site leading to decrease the electron-hole pair and consequently enhancing the photodegradation.

  • 35.
    Adhikari, Arindam
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Pani, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Deidinaitei, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Blomberg, Eva
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Electrochemical behavior and anticorrosion properties of modified polyaniline dispersed in polyvinylacetate coating on carbon steel2008In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 53, no 12, p. 4239-4247Article in journal (Refereed)
    Abstract [en]

    Conducting polyaniline (Pani) was prepared in the presence of methane sulfonic acid (MeSA) as dopant by chemical oxidative polymerization. The Pani-MeSA polymer was characterized by FT-IR, UV-vis, X-ray diffraction (XRD) and impedance spectroscopy. The polyrner was dispersed in polyvinylacetate and coated oil carbon steel samples by a dipping method. The electrochemical behavior and anticorrosion properties of the coating, oil carbon steel in 3% NaCl were investigated using Open-circuit Potential (OCP) versus time of exposure, and electrochemical techniques including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and cyclic voltammetry (CV). During initial exposure, the OCP dropped about 0.35 V and the interfacial resistance increased several times, indicating I certain reduction of the polymer and oxidation of the steel surface. Later the OCP shifted to the noble direction and remained at a stable value during the exposure up to 60 days. The EIS monitoring also revealed the initial change and later stabilization of the coating. The stable high OCP and low coating impedance Suggest that the conducting polymer maintains its oxidative state and provides corrosion protection for carbon steel through out the investigated period. The polarization curves and CV show that the conducting polymer coating induces a passive-like behavior and greatly reduces the corrosion of carbon steel.

  • 36.
    Adler, Anna
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology.
    Fritsch, Marlene
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology.
    Fromell, Karin
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology.
    Leneweit, Gero
    Carl Gustav Carus-Institute, Association for the Promotion of Cancer Therapy, Niefern-Öschelbronn, Germany.
    Ekdahl, Kristina N.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology. Linnaeus Center of Biomaterials Chemistry, Linnaeus University, SE-391 82 Kalmar, Sweden.
    Nilsson, Bo
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology.
    Teramura, Yuji
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology. Cellular and Molecular Biotechnology Research Institute (CMB), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central Fifth, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan; Master's/Doctoral Program in Life Science Innovation (T-LSI), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan.
    Regulation of the innate immune system by fragmented heparin-conjugated lipids on lipid bilayered membranes in vitro2023In: Journal of materials chemistry. B, ISSN 2050-750X, E-ISSN 2050-7518, Vol. 11, no 46, p. 11121-11134Article in journal (Refereed)
    Abstract [en]

    Surface modification with heparin is a powerful biomaterial coating strategy that protects against innate immunity activation since heparin is a part of the proteoglycan heparan sulfate on cell surfaces in the body. We studied the heparinization of cellular and material surfaces via lipid conjugation to a heparin-binding peptide. In the present study, we synthesized fragmented heparin (fHep)-conjugated phospholipids and studied their regulation of the innate immune system on a lipid bilayered surface using liposomes. Liposomes have versatile applications, such as drug-delivery systems, due to their ability to carry a wide range of molecules. Owing to their morphological similarity to cell membranes, they can also be used to mimic a simple cell-membrane to study protein–lipid interactions. We investigated the interaction of complement-regulators, factor H and C4b-binding protein (C4BP), as well as the coagulation inhibitor antithrombin (AT), with fHep-lipids on the liposomal surface. Herein, we studied the ability of fHep-lipids to recruit factor H, C4BP, and AT using a quartz crystal microbalance with dissipation monitoring. With dynamic light scattering, we demonstrated that liposomes could be modified with fHep-lipids and were stable up to 60 days at 4 °C. Using a capillary western blot-based method (Wes), we showed that fHep-liposomes could recruit factor H in a model system using purified proteins and assist in the degradation of the active complement protein C3b to iC3b. Furthermore, we found that fHep-liposomes could recruit factor H and AT from human plasma. Therefore, the use of fHep-lipids could be a potential coating for liposomes and cell surfaces to regulate the immune system on the lipid surface.

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  • 37. Adolfsson, Erik
    et al.
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Effects of granule density on strength and granule related defects in zirconia2012In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 32, no 11, p. 2653-2659Article in journal (Refereed)
    Abstract [en]

    A suspension of zirconia powder (TZ3YSE) with a solids loading of 50 vol% was prepared by ball milling. Binders were added and some of the suspension was diluted to 40, 30 and 20 vol% before freeze granulation was performed. A spray dried material (TZ3YSEB) was used as a reference. The pore size distribution of the different granules was evaluated and from the microstructure it was shown that inhomogeneities were present in both the freeze granulated as well as in the spray dried granules. In addition, the density, microstructure as well as the strength of sintered materials prepared from the granules were studied. The results showed that a high green density or sintered density was not sufficient in order to achieve a high strength material. It was further shown that the strength was significantly influenced by the granule density and not by the inhomogeneities found in the granules.

  • 38.
    Adolfsson, Karin H. H.
    et al.
    KTH Royal Inst Technol, Dept Fibre & Polymer Technol, S-10044 Stockholm, Sweden..
    Huang, Ping
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Golda-Cepa, Monika
    Jagiellonian Univ, Fac Chem, PL-30387 Krakow, Poland..
    Xu, Huan
    China Univ Min & Technol, Sch Mat Sci & Phys, Xuzhou 221116, Peoples R China..
    Kotarba, Andrzej
    Jagiellonian Univ, Fac Chem, PL-30387 Krakow, Poland..
    Hakkarainen, Minna
    KTH Royal Inst Technol, Dept Fibre & Polymer Technol, S-10044 Stockholm, Sweden..
    Scavenging of DPPH by Persistent Free Radicals in Carbonized Particles2023In: Advanced Sustainable Systems, ISSN 2366-7486, Vol. 7, no 3, article id 2200425Article in journal (Refereed)
    Abstract [en]

    Persistent free radicals (PFR) in carbonized particles may play a role in degradation of environmental compounds. The influence of PFR is evaluated in various carbonized particles on their radical scavenging efficiency upon the common radical indicator 2-2-diphenyl-1-picrylhydrazyl (DPPH). Carbonized particles are derived by hydrothermal carbonization of glucose (C-W) or glucose and urea (NC-W) and ionothermal carbonization of glucose and urea ionic liquid (IL) (NC-IL). The carbonized materials contain OH/COOH, C=C, and C-O functionalities. The addition of urea introduces NH/NH2 functionalities. The content of polar surface groups is lower in IL-processed NC-IL. The scavenging ability, measured as DPPH UV–vis absorption decline, increases with concentration and time for all particles, while the efficiency changes are in the order of C-W > NC-W > NC-IL. Electron paramagnetic resonance analysis reveals similar radical concentration in all carbonized materials studied. The difference in efficiency is, thus, not directly related to the PFR concentration but rather to the type of PFR, surface functionalities and/or scavenging mechanism. According to the g-values, radicals in these particles are carbon-centered. The minor variation in g-values suggests interactions between the radicals and their environmental functional groups. This provides insights into the influence of PFR in carbonized materials on their radical scavenging efficiency.

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  • 39.
    Adorno Lopes, Denise
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Engineering.
    Wilson, T. L.
    Univ South Carolina, Columbia, SC 29208 USA..
    Kocevski, V.
    Univ South Carolina, Columbia, SC 29208 USA..
    Moore, E. E.
    Univ South Carolina, Columbia, SC 29208 USA..
    Besmann, T. M.
    Univ South Carolina, Columbia, SC 29208 USA..
    Wood, E. Sooby
    Univ Texas San Antonio, San Antonio, TX USA..
    White, J. T.
    Los Alamos Natl Lab, Los Alamos, NM USA..
    Nelson, A. T.
    Los Alamos Natl Lab, Los Alamos, NM USA..
    Middleburgh, S. C.
    Westinghouse Elect Sweden AB, Vasteras, Sweden.;Bangor Univ, Nucl Futures Inst, Bangor LL57 1UT, Gwynedd, Wales..
    Claisse, Antoine
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Engineering.
    Experimental and computational assessment of U-Si-N ternary phases2019In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 516, p. 194-201Article in journal (Refereed)
    Abstract [en]

    Uranium nitride-silicide composites are being considered as a high-density and high thermal conductivity fuel option for light water reactors. During development, chemical interactions were observed near the silicide melting point which resulted in formation of an unknown U-Si-N ternary phase. In the present work, U-Si-N composite samples were produced by arc-melting U3Si2 under an argon-nitrogen atmosphere to form the ternary phase. The resulting samples were characterized by SEM/EDS-EPMA and XRD, and demonstrated an equilibrium between U3Si2, UN, USi and a U-Si-N phase with a distinct crystallographic structure. Rietveld refinement of the ternary structure was performed, considering the ternary structures existent in the analogue U-Si-C system, and a good fit was obtained for the hexagonal U(20)Si(16)N(3 )phase. DFT + U calculations were performed in parallel to evaluate the thermodynamic and dynamic stability of the ternaries U20Si16N3 and U3Si2N2. The calculated enthalpy of formation and phonon dispersion support the existence of stable U20Si16N3 and U3Si2N2, although some soft modes in the U(20)Si(16)N(3)( )phase phonons are observed. The results presented here thus demonstrate the occurrence of at least one ternary phase in the U-Si-N system.

  • 40.
    Adranno, Brando
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Complex phase behaviour of organic-inorganic green-emitting ionic manganese halidesManuscript (preprint) (Other academic)
  • 41.
    Adranno, Brando
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    In Light of Ionic Materials: A short exploration of ionic materials for light-related applications2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Ionic liquids (ILs) have been one of the most attractive classes of materials of the last decades. The reason behind this is their peculiar set of properties, which enable their possible application in several research fields. ILs are salts that exhibit a very low melting point, which has been arbitrarily defined to be below 100 °C. Due to their ionic nature, ILs have little to no vapor pressure and they often demonstrate good electrical conductivity and high thermal and electrochemical stability. In this work, the focus is directed toward the exploitation of ILs for the engineering of materials that can have a primary role in light-emitting or light-absorbing devices. Materials belonging to the first type are explored in Papers I-III, while the ones belonging to the second are tackled in Papers IV and V.

    There has always been a struggle to find a balance between costs and the efficiency of emitting materials for application in dedicated devices. In Papers I-III, two strategies are taken into account to address this issue. Finding inspiration from ionic complexes of Mn(II), newly designed ionic materials and ILs emitting green light are proposed as an alternative to the more expensive heavy metals-based ones such as Ir(III) and Pt(II). Coming closer to an ideal compromise of cost and performance, fully organic and extremely cheap low-melting salts based on the 8-hydroxyquinoline unit were prepared. These compounds revealed efficient fluorescence in the blue region of the spectrum for such simple molecules, paving the way for the preparation of possibly inexpensive light-emitting devices.

    In Paper IV, direct absorption of light is taken into consideration with photoresponsive ionic liquids, which undergo cis-trans isomerization. Due to this feature and their ionic nature, these materials could be adopted into photoswitches. Additionally, the effect of functional groups on the isomerization of the ILs and on the ability of the materials to undergo mesophase formation was studied.

    One of the key components of dye-sensitized solar cells is the electrolytic mediator sandwiched between two electrodes. This has been a matter of intense study due to issues regarding its stability, which impair the device's performance. ILs can be adopted in devices to solve this issue. In Paper V, triazolium ILs allowed the manufacturing of devices with higher efficiencies and longer lifetimes than the ones realized with imidazolium relatives. These materials allowed for the stability of the ionic couple I-/I3- and moisture resistance due to their non-hygroscopic nature.

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  • 42.
    Adranno, Brando
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    The 8-Hydroxyquinolinium Cation as a Lead Structure for Efficient Colour-Tunable Ionic Small Molecule Emitting MaterialsManuscript (preprint) (Other academic)
  • 43.
    Adranno, Brando
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Renier, Olivier
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bousrez, Guillaume
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Paterlini, Veronica
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Baryshnikov, Glib V.
    Smetana, Volodymyr
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Tang, Shi
    Ågren, Hans
    Metlen, Andreas
    Edman, Ludvig
    Mudring, Anja-Verena
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Aarhus University, Denmark.
    Rogers, Robin D.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). The Queen's University of Belfast, Northern Ireland; The University of Alabama, USA.
    The 8-Hydroxyquinolinium Cation as a Lead Structure for Efficient Color-Tunable Ionic Small Molecule Emitting Materials2023In: Advanced Photonics Research, E-ISSN 2699-9293, Vol. 4, no 3, article id 2200279Article in journal (Refereed)
    Abstract [en]

    Albeit tris(8-hydroxyquinolinato) aluminum (Alq3) and its derivatives are prominent emitter materials for organic lighting devices, and the optical transitions occur among ligand-centered states, the use of metal-free 8-hydroxyquinoline is impractical as it suffers from strong nonradiative quenching, mainly through fast proton transfer. Herein, it is shown that the problem of rapid proton exchange and vibration quenching of light emission can be overcome not only by complexation, but also by organization of the 8-hydroxyquinolinium cations into a solid rigid network with appropriate counter-anions (here bis(trifluoromethanesulfonyl)imide). The resulting structure is stiffened by secondary bonding interactions such as π-stacking and hydrogen bonds, which efficiently block rapid proton transfer quenching and reduce vibrational deactivation. Additionally, the optical properties are tuned through methyl substitution from deep blue (455 nm) to blue-green (488 nm). Time-dependent density functional theory (TDFT) calculations reveal the emission to occur from which an unexpectedly long-lived S1 level, unusual for organic fluorophores. All compounds show comparable, even superior photoluminescence compared to Alq3 and related materials, both as solids and thin films with quantum yields (QYs) up to 40–50%. In addition, all compounds show appreciable thermal stability with decomposition temperatures above 310 °C.

  • 44.
    Adranno, Brando
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Tang, Shi
    Paterlini, Veronica
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Smetana, Volodymyr
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Aarhus University, Denmark.
    Renier, Olivier
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bousrez, Guillaume
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Aarhus University, Denmark.
    Edman, Ludvig
    Mudring, Anja-Verena
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Aarhus University, Denmark.
    Broadband White-Light-Emitting Electrochemical Cells2023In: Advanced Photonics Research, E-ISSN 2699-9293, Vol. 4, no 5, article id 2200351Article in journal (Refereed)
    Abstract [en]

    Emerging organic light-emitting devices, such as light-emitting electrochemical cells (LECs), offer a multitude of advantages but currently suffer from that most efficient phosphorescent emitters are based on expensive and rare metals. Herein, it is demonstrated that a rare metal-free salt, bis(benzyltriphenylphosphonium)tetrabromidomanganate(II) ([Ph3PBn]2[MnBr4]), can function as the phosphorescent emitter in an LEC, and that a careful device design results in the fact that such a rare metal-free phosphorescent LEC delivers broadband white emission with a high color rendering index (CRI) of 89. It is further shown that broadband emission is effectuated by an electric-field-driven structural transformation of the original green-light emitter structure into a red-emitting structure. 

  • 45.
    Adranno, Brando
    et al.
    Physical Materials Chemistry, Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden.
    Tang, Shi
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Paterlini, Veronica
    Physical Materials Chemistry, Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden.
    Smetana, Volodymyr
    Physical Materials Chemistry, Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden; Intelligent Advanced Materials (iAM), Department of Biological and Chemical Engineering and iNANO, Aarhus University, 8000 Aarhus C, Denmark.
    Renier, Olivier
    Physical Materials Chemistry, Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden.
    Bousrez, Guillaume
    Physical Materials Chemistry, Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden; Intelligent Advanced Materials (iAM), Department of Biological and Chemical Engineering and iNANO, Aarhus University, 8000 Aarhus C, Denmark.
    Edman, Ludvig
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Mudring, Anja-Verena
    Physical Materials Chemistry, Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden; Intelligent Advanced Materials (iAM), Department of Biological and Chemical Engineering and iNANO, Aarhus University, 8000 Aarhus C, Denmark.
    Broadband white-light-emitting electrochemical cells2023In: Advanced Photonics Research, ISSN 2699-9293, Vol. 4, no 5, article id 2200351Article in journal (Refereed)
    Abstract [en]

    Emerging organic light-emitting devices, such as light-emitting electrochemical cells (LECs), offer a multitude of advantages but currently suffer from that most efficient phosphorescent emitters are based on expensive and rare metals. Herein, it is demonstrated that a rare metal-free salt, bis(benzyltriphenylphosphonium)tetrabromidomanganate(II) ([Ph3PBn]2[MnBr4]), can function as the phosphorescent emitter in an LEC, and that a careful device design results in the fact that such a rare metal-free phosphorescent LEC delivers broadband white emission with a high color rendering index (CRI) of 89. It is further shown that broadband emission is effectuated by an electric-field-driven structural transformation of the original green-light emitter structure into a red-emitting structure.

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  • 46.
    Afrasiabi, Roodabeh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Jokilaakso, Nima
    KTH, School of Biotechnology (BIO), Protein Technology.
    Schmidt, Torsten
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Björk, P.
    Eriksson Karlström, Amelie
    KTH, School of Biotechnology (BIO), Protein Technology.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Effect of microwave-assisted silanization on sensing properties of silicon nanoribbon FETs2015In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 209, p. 586-595Article in journal (Refereed)
    Abstract [en]

    An important concern with using silicon nanoribbon field-effect transistors (SiNR FET) for ion-sensing is the pH-response of the gate oxide surface. Depending on the application of the FET sensor, this response has to be chemically manipulated. Thus in silicon oxide-gated pH-sensors with integrated sensor and reference FETS, a surface with high pH-sensitivity, compared to the bare gate oxide, is required in the sensor FETs (SEFET), whereas in the reference FETs (REFET) the surface has to be relatively pH-insensitive. In order to control the sensitivity and chemistry of the oxide surface of the nanoribbons, a silanization reagent with a functional group is often self-assembled on the SiNR surface. Choice of a silanization reaction that results in a self-assembled layer on a silicon oxide surface has been studied extensively over the past decades. However, the effect of various self-assembled layers such as monolayers or mixed layers on the electrical response of SiNR FETs in aqueous solution needs to be exploited further, especially for future integrated SEFET/REFET systems. In this work, we have performed a comprehensive study on 3-aminopropyltriethoxysilane (APTES) silanization of silicon oxide surfaces using microwave (MW) heating as a new biocompatible route to conventional methods. A set of complementary surface characterization techniques (ellipsometry, AFM and ATR-FTIR) was used to analyze the properties of the APTES layer deposited on the silicon surface. We have found that a uniform monolayer can be achieved within 10 min by heating the silanization solution to 75 degrees C using MW heating. Furthermore, electrical measurements suggest that little change in device performance is observed after exposure to MW irradiation. Real-time pH measurements indicate that a uniform APTES monolayer not only reduces the pH sensitivity of SiNR FET by passivating the surface silanol groups, but also makes the device less sensitive to cation concentration in the background electrolyte. Our silanization route proves promising for future chemical surface modification of on-chip REFETs.

  • 47.
    Afroze, Shammya
    et al.
    Univ Brunei Darussalam, Fac Integrated Technol, Jalan Tungku Link, BE-1410 Gadong, Brunei; Chalmers Univ Technol, Dept Chem & Chem Engn, SE-41296 Gothenburg, Sweden..
    Torino, Nico
    Chalmers Univ Technol, Dept Chem & Chem Engn, SE-41296 Gothenburg, Sweden..
    Reza, Md Sumon
    Univ Brunei Darussalam, Fac Integrated Technol, Jalan Tungku Link, BE-1410 Gadong, Brunei..
    Radenahmad, Nikdalila
    Univ Brunei Darussalam, Fac Integrated Technol, Jalan Tungku Link, BE-1410 Gadong, Brunei..
    Cheok, Quentin
    Univ Brunei Darussalam, Fac Integrated Technol, Jalan Tungku Link, BE-1410 Gadong, Brunei..
    Henry, Paul F.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Rutherford Appleton Lab, ISIS Pulsed Neutron & Muon Facil, Harwell Campus, Didcot OX11 0QX, Oxon, England..
    Azad, Abul K.
    Univ Brunei Darussalam, Fac Integrated Technol, Jalan Tungku Link, BE-1410 Gadong, Brunei..
    Structure-conductivity relationship of PrBaMnMoO6-δ through in-situ measurements: A neutron diffraction study2021In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 47, no 1, p. 541-546Article in journal (Refereed)
    Abstract [en]

    The structural and electrochemical properties of the double perovskite-type oxide, PrBaMnMoO6-δ, was investigated using neutron diffraction with in-situ conductivity measurement under a dry Argon atmosphere from 25 °C to 700 °C. A Rietveld refinement of the neutron diffraction data confirmed monoclinic symmetry in the P21/n space group. Rietveld refinement also confirms the unit cell parameters of a = 5.6567 (1) Å, b = 5.6065 (2) Å, c = 7.9344 (1) Å and β = 84.43° with reliable atomic positions and refinement factors (R-factors). Neutron diffraction data refinement shows two minor phases (< 5%), an orthorhombic AB2O5 type phase of PrMn2O5 in the Pbam (No. 32) space group with unit cell parameters, a = 7.9672 (1) Å, b = 8.9043 (2) Å and c = 5.8540 (1) Å and a scheelite phase of BaMoO4 in the tetragonal I41/a (88) space group with the unit cell parameters, a = b = 5.9522 (1) Å, and c = 12.3211 (2) Å. Morphological images revealed a porous and intertwined microstructure. In-situ conductivity measurement shows that the total conductivity of this material was 130.84 Scm−1 at 700 °C.

  • 48.
    Afroze, Shammya
    et al.
    Univ Brunei Darussalam, Fac Integrated Technol, Jalan Tungku Link, BE-1410 Bandar Seri Begawan, Brunei; Chalmers Univ Technol, Dept Chem & Chem Engn, SE-41296 Gothenburg, Sweden.
    Yilmaz, Duygu
    Chalmers Univ Technol, Dept Chem & Chem Engn, SE-41296 Gothenburg, Sweden.
    Reza, Md Sumon
    Univ Brunei Darussalam, Fac Integrated Technol, Jalan Tungku Link, BE-1410 Bandar Seri Begawan, Brunei.
    Henry, Paul F.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Rutherford Appleton Lab, ISIS Pulsed Neutron & Muon Facil, Harwell Campus, Didcot OX11 0QX, Oxon, England.
    Cheok, Quentin
    Univ Brunei Darussalam, Fac Integrated Technol, Jalan Tungku Link, BE-1410 Bandar Seri Begawan, Brunei.
    Zaini, Juliana H.
    Univ Brunei Darussalam, Fac Integrated Technol, Jalan Tungku Link, BE-1410 Bandar Seri Begawan, Brunei.
    Azad, Abul K.
    Univ Brunei Darussalam, Fac Integrated Technol, Jalan Tungku Link, BE-1410 Bandar Seri Begawan, Brunei.
    Issakhov, Alibek
    Al Farabi Kazakh Natl Univ, Dept Math & Comp Modelling, Fac Mech & Math, Alma Ata, Kazakhstan.
    Sadeghzadeh, Milad
    Univ Tehran, Dept Renewable Energy & Environm Engn, Tehran, Iran.
    Investigation of Structural and Thermal Evolution in Novel Layered Perovskite NdSrMn2O5+δ via Neutron Powder Diffraction and Thermogravimetric Analysis2020In: International Journal of Chemical Engineering, ISSN 1687-806X, E-ISSN 1687-8078, Vol. 2020, article id 6642187Article in journal (Refereed)
    Abstract [en]

    Neutron diffraction is one of the best methods for structural analysis of a complex, layered perovskite material with low symmetry by accurately detecting the oxygen positions through octahedral tilting. In this research, the crystal structure of NdSrMn2O5+δ was identified through X-ray diffraction (XRD) and neutron powder diffraction (NPD) at room temperature (RT), which indicated the formation of a layered structure in orthorhombic symmetry in the Pmmm (no. 47) space group. Rietveld refinement of the neutron diffraction data has confirmed the orthorhombic symmetry with unit cell parameters (a = 3.8367 (1) Å, b = 3.8643 (2) Å, and c = 7.7126 (1) Å), atomic positions, and oxygen occupancy. Thermogravimetric analysis revealed the total weight loss of about 0.10% for 20–950°C temperature, which occurred mainly to create oxygen vacancies at high temperatures. Rietveld analyses concurred with the XRD and neutron data allowing correlation of occupancy factors of the oxygen sites.

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  • 49.
    Aftab, Umair
    et al.
    Mehran Univ Engn & Technol, Pakistan.
    Tahira, Aneela
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Gradone, Alessandro
    CNR IMM, Italy; Univ Bologna, Italy.
    Morandi, Vittorio
    CNR IMM, Italy.
    Abro, Muhammad Ishaq
    Mehran Univ Engn & Technol, Pakistan.
    Baloch, Muhammad Moazam
    Mehran Univ Engn & Technol, Pakistan.
    Bhatti, Adeel Liaquat
    Univ Sindh, Pakistan.
    Nafady, Ayman
    King Saud Univ, Saudi Arabia.
    Vomiero, Alberto
    Lulea Univ Technol, Sweden; Ca Foscari Univ Venice, Italy.
    Ibupoto, Zafar Hussain
    Univ Sindh, Pakistan.
    Two step synthesis of TiO2-Co3O4 composite for efficient oxygen evolution reaction2021In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 46, no 13, p. 9110-9122Article in journal (Refereed)
    Abstract [en]

    For an active hydrogen gas generation through water dissociation, the sluggish oxygen evolution reaction (OER) kinetics due to large overpotential is a main hindrance. Herein, a simple approach is used to produce composite material based on TiO2/Co3O4 for efficient OER and overpotential is linearly reduced with increasing amount of TiO2. The scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) investigations reveal the wire like morphology of composite materials, formed by the self-assembly of nanoparticles. The titania nanoparticles were homogenously distributed on the larger Co3O4 nanoparticles. The powder x-ray diffraction revealed a tetragonal phase of TiO2 and the cubic phase of Co3O4 in the composite materials. Composite samples with increasing TiO2 content were obtained (18%, 33%, 41% and 65% wt.). Among the composites, cobalt oxide-titanium oxide with the highest TiO2 content (CT-20) possesses the lowest overpotential for OER with a Tafel slope of 60 mV dec(-1) and an exchange current density of 2.98 x 10(-3)A/cm(2). The CT-20 is highly durable for 45 h at different current densities of 10, 20 and 30 mA/cm(2). Electrochemical impedance spectroscopy (EIS) confirmed the fast charge transport for the CT-20 sample, which potentially accelerated the OER kinetics. These results based on a two-step methodology for the synthesis of TiO2/Co3O4 material can be useful and interesting for various energy storage and energy conversion systems. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

  • 50.
    Aftab, Umair
    et al.
    Mehran Univ Engn and Technol, Pakistan.
    Tahira, Aneela
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Mazzaro, Raffaello
    Italian Natl Res Council, Italy.
    Abro, Muhammad Ishaq
    Mehran Univ Engn and Technol, Pakistan.
    Baloch, Muhammad Moazam
    Mehran Univ Engn and Technol, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Yu, Cong
    Chinese Acad Sci, Peoples R China.
    Ibupoto, Zafar Hussain
    Univ Sindh, Pakistan.
    The chemically reduced CuO-Co3O4 composite as a highly efficient electrocatalyst for oxygen evolution reaction in alkaline media2019In: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761, Vol. 9, no 22, p. 6274-6284Article in journal (Refereed)
    Abstract [en]

    The fabrication of efficient, alkaline-stable and nonprecious electrocatalysts for the oxygen evolution reaction is highly needed; however, it is a challenging task. Herein, we report a noble metal-free advanced catalyst, i.e. the chemically reduced mixed transition metal oxide CuO-Co3O4 composite, with outstanding oxygen evolution reaction activity in alkaline media. Sodium borohydride (NaBH4) was used as a reducing agent for the mixed transition metal oxide CuO-Co3O4. The chemically reduced composite carried mixed valence states of Cu and Co, which played a dynamic role in driving an excellent oxygen evolution reaction process. The X-ray photo-electron spectroscopy (XPS) study confirmed high density of active sites in the treated sample with a large number of oxygen vacancies. The developed electrocatalyst showed the lowest overpotential of 144.5 mV vs. the reversible hydrogen electrode (RHE) to achieve the current density of 40 mA cm(-2) and remained stable for 40 hours throughout the chronoamperometry test at the constant potential of 1.39 V vs. RHE. Moreover, the chemically reduced composite was highly durable. Electrochemical impedance spectroscopy (EIS) confirmed the low charge transfer resistance of 13.53 ohms for the chemically reduced composite, which was 50 and 26 times smaller than that of Co3O4 and untreated CuO-Co3O4, respectively. The electrochemically active surface area for the chemically reduced composite was found to be greater than that for pristine CuO, Co3O4 and untreated pristine CuO-Co3O4. These findings reveal the possibility of a new gateway for the capitalization of a chemically reduced sample into diverse energy storage and conversion systems such as lithium-ion batteries and supercapacitors.

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