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Author Yang, C.; Batuk, M.; Jacquet, Q.; Rousse, G.; Yin, W.; Zhang, L.; Hadermann, J.; Abakumov, A.M.; Cibin, G.; Chadwick, A.; Tarascon, J.-M.; Grimaud, A. pdf  url
doi  openurl
  Title Revealing pH-Dependent Activities and Surface Instabilities for Ni-Based Electrocatalysts during the Oxygen Evolution Reaction Type A1 Journal article
  Year 2018 Publication ACS energy letters Abbreviated Journal Acs Energy Lett  
  Volume Issue Pages 2884-2890  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Multiple electrochemical processes are involved at the catalyst/ electrolyte interface during the oxygen evolution reaction (OER). With the purpose of elucidating the complexity of surface dynamics upon OER, we systematically studied two Ni-based crystalline oxides (LaNiO3−δ and La2Li0.5Ni0.5O4) and compared them with the state-of-the-art Ni−Fe (oxy)- hydroxide amorphous catalyst. Electrochemical measurements such as rotating ring disk electrode (RRDE) and electrochemical quartz microbalance microscopy (EQCM) coupled with a series of physical characterizations including transmission electron microscopy (TEM) and X-ray absorption spectroscopy (XAS) were conducted to unravel the exact pH effect on both the OER activity and the catalyst stability. We demonstrate that for Ni-based crystalline catalysts the rate for surface degradation depends on the pH and is greater than the rate for surface reconstruction. This behavior is unlike that for the amorphous Ni oxyhydroxide catalyst, which is found to be more stable and pH-independent.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000453805100005 Publication Date 2018-11-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 2380-8195 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access Not_Open_Access: Available from 06.11.2019  
  Notes C.Y., J.-M.T., and A.G. acknowledge funding from the European Research Council (ERC) (FP/2014)/ERC GrantProject 670116-ARPEMA. A.G. acknowledges financial support from the ANR MIDWAY (Project ID ANR-17-CE05- 0008). We acknowledge Diamond Light Source for time awarded to the Energy Materials BAG on Beamline B18, under Proposal sp12559. Approved Most recent IF: NA  
  Call Number EMAT @ emat @c:irua:155046 Serial 5067  
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Author Vladimirova, N.V.; Frolov, A.S.; Sanchez-Barriga, J.; Clark, O.J.; Matsui, F.; Usachov, D.Y.; Muntwiler, M.; Callaert, C.; Hadermann, J.; Neudachina, V.S.; Tamm, M.E.; Yashina, L.V. pdf  url
doi  openurl
  Title Occupancy of lattice positions probed by X-ray photoelectron diffraction : a case study of tetradymite topological insulators Type A1 Journal article
  Year 2023 Publication Surfaces and interfaces Abbreviated Journal  
  Volume 36 Issue Pages 102516-10  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Occupancy of different structural positions in a crystal lattice often seems to play a key role in material prop-erties. Several experimental techniques have been developed to uncover this issue, all of them being mostly bulk sensitive. However, many materials including topological insulators (TIs), which are among the most intriguing modern materials, are intended to be used in devices as thin films, for which the sublattice occupancy may differ from the bulk. One of the possible approaches to occupancy analysis is X-ray Photoelectron Diffraction (XPD), a structural method in surface science with chemical sensitivity. We applied this method in a case study of Sb2(Te1-xSex)3 mixed crystals, which belong to prototypical TIs. We used high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) as a reference method to verify our analysis. We revealed that the XPD data for vacuum cleaved bulk crystals are in excellent agreement with the reference ones. Also, we demonstrate that the anion occupancy near a naturally formed surface can be rather different from that of the bulk. The present results are relevant for a wide range of compositions where the system remains a topological phase, as we ultimately show by probing the transiently occupied topological surface state above the Fermi level by ultrafast photoemission.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000901694900001 Publication Date 2022-11-28  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 2468-0230 ISBN Additional Links UA library record; WoS full record  
  Impact Factor 6.2 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 6.2; 2023 IF: NA  
  Call Number UA @ admin @ c:irua:193502 Serial 7327  
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Author Augustyns, V.; van Stiphout, K.; Joly, V.; Lima, T.A.L.; Lippertz, G.; Trekels, M.; Menendez, E.; Kremer, F.; Wahl, U.; Costa, A.R.G.; Correia, J.G.; Banerjee, D.; Gunnlaugsson, H.P.; von Bardeleben, J.; Vickridge, I.; Van Bael, M.J.; Hadermann, J.; Araujo, J.P.; Temst, K.; Vantomme, A.; Pereira, L.M.C. url  doi
openurl 
  Title Evidence of tetragonal distortion as the origin of the ferromagnetic ground state in gamma-Fe nanoparticles Type A1 Journal article
  Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 96 Issue 17 Pages 174410  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract <script type='text/javascript'>document.write(unpmarked('gamma-Fe and related alloys are model systems of the coupling between structure and magnetism in solids. Since different electronic states (with different volumes and magnetic ordering states) are closely spaced in energy, small perturbations can alter which one is the actual ground state. Here, we demonstrate that the ferromagnetic state of gamma-Fe nanoparticles is associated with a tetragonal distortion of the fcc structure. Combining a wide range of complementary experimental techniques, including low-temperature Mossbauer spectroscopy, advanced transmission electron microscopy, and synchrotron radiation techniques, we unambiguously identify the tetragonally distorted ferromagnetic ground state, with lattice parameters a = 3.76(2) angstrom and c = 3.50(2) angstrom, and a magnetic moment of 2.45(5) mu(B) per Fe atom. Our findings indicate that the ferromagnetic order in nanostructured gamma-Fe is generally associated with a tetragonal distortion. This observation motivates a theoretical reassessment of the electronic structure of gamma-Fe taking tetragonal distortion into account.'));  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication New York, N.Y Editor  
  Language Wos 000414525200005 Publication Date 2017-11-07  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 1 Open Access OpenAccess  
  Notes ; The authors thank the Fund for Scientific Research-Flanders, the Concerted Research Action of the KU Leuven (GOA/14/007), the KU Leuven BOF (STRT/14/002), the Hercules Foundation, the Portuguese Foundation for Science and Technology (CERN/FIS-NUC/0004/2015), and the European Union Seventh Framework through ENSAR2 (European Nuclear Science and Applications Research, Project No. 654002), and SPIRIT (Support of Public and Industrial Research Using Ion Beam Technology, Contract No. 227012). We acknowledge the European Synchrotron Radiation Facility (ESRF) for providing beam time (experiments 26-01-1018, 26-01-1057, 20-02-728, HC-1850, HC-2208), as well as C. Baehtz, N. Boudet, and N. Blancand for support during the experiments. We acknowledge the ISOLDE-CERN facility for providing beam time (experiment IS580) and technical assistance. The authors (L.M.C.P., F.K.) acknowledge the facilities and the scientific and technical assistance of the Australian Microscopy & Microanalysis Research Facility at the Centre for Advanced Microscopy, Australian National University. We also acknowledge the contribution of Prof. Mark Ridgway (Australian National University), who passed away before the work was completed. ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:147387 Serial 4873  
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Author Sanchez-Barriga, J.; Aguilera, I.; Yashina, L., V; Tsukanova, D.Y.; Freyse, F.; Chaika, A.N.; Callaert, C.; Abakumov, A.M.; Hadermann, J.; Varykhalov, A.; Rienks, E.D.L.; Bihlmayer, G.; Blugel, S.; Rader, O. url  doi
openurl 
  Title Anomalous behavior of the electronic structure of (Bi1-xInx)2Se3across the quantum phase transition from topological to trivial insulator Type A1 Journal article
  Year 2018 Publication Physical review B Abbreviated Journal  
  Volume 98 Issue 23 Pages 235110  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Using spin- and angle-resolved photoemission spectroscopy and relativistic many-body calculations, we investigate the evolution of the electronic structure of (Bi1-xInx)(2)Se-3)(2)Se-3 bulk single crystals around the critical point of the trivial to topological insulator quantum-phase transition. By increasing x, we observe how a surface gap opens at the Dirac point of the initially gapless topological surface state of Bi2Se3, leading to the existence of massive fermions. The surface gap monotonically increases for a wide range of x values across the topological and trivial sides of the quantum-phase transition. By means of photon-energy-dependent measurements, we demonstrate that the gapped surface state survives the inversion of the bulk bands which occurs at a critical point near x = 0.055. The surface state exhibits a nonzero in-plane spin polarization which decays exponentially with increasing x, and which persists in both the topological and trivial insulator phases. Our calculations reveal qualitative agreement with the experimental results all across the quantum-phase transition upon the systematic variation of the spin-orbit coupling strength. A non-time-reversal symmetry-breaking mechanism of bulk-mediated scattering processes that increase with decreasing spin-orbit coupling strength is proposed as explanation.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000452322800003 Publication Date 2018-12-05  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:156240 Serial 7462  
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Author Vishwakarma, M.; Batra, Y.; Hadermann, J.; Singh, A.; Ghosh, A.; Mehta, B.R. pdf  doi
openurl 
  Title Exploring the role of graphene oxide as a co-catalyst in the CZTS photocathodes for improved photoelectrochemical properties Type A1 Journal article
  Year 2022 Publication ACS applied energy materials Abbreviated Journal  
  Volume 5 Issue 6 Pages 7538-7549  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The hydrogen evolution properties of CZTS heterostructure photocathodes are reported with graphene oxide (GO) as a co-catalyst layer coated by a drop-cast method and an Al2O3 protection layer fabricated using atomic layer deposition. In the CZTS absorber, a minor deviation from stoichiometry across the cross section of the thin film results in nanoscale growth of spurious phases, but the kesterite phase remains the dominant phase. We have investigated the band alignment parameters such as the band gap, work function, and Fermi level position that are crucial for making kesterite-based heterostructure devices. The photocurrent density in the photocathode CZTS/CdS/ZnO is found to be improved to -4.71 mAmiddotcm(-2) at -0.40 V-RHE, which is 3 times that of the pure CZTS. This enhanced photoresponse can be attributed to faster carrier separation at p-n junction regions driven by upward band bending at CZTS grain boundaries and the ZnO layer. GO as a co-catalyst over the heterostructure photocathode significantly improves the photocurrent density to -6.14 mAmiddotcm(-2) at -0.40 V-RHE by effective charge migration in the CZTS/CdS/ZnO/GO configuration, but the onset potential shifts only after application of the Al2O3 protection layer. Significant photocurrents of -29 mAmiddotcm(-2) at -0.40 V-RHE and -8 mAmiddotcm(-2) at 0 V-RHE are observed, with an onset potential of 0.7 V-RHE in CZTS/CdS/ZnO/GO/Al2O3. The heterostructure configuration and the GO co-catalyst reduce the charge-transfer resistance, while the Al2O3 top layer provides a stable photocurrent for a prolonged time (similar to 16 h). The GO co-catalyst increases the flat band potential from 0.26 to 0.46 V-RHE in CZTS/CdS/ZnO/GO, which supports the bias-induced band bending at the electrolyte-electrode interface.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000820418400001 Publication Date 2022-05-24  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 2574-0962 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 6.4 Times cited Open Access Not_Open_Access  
  Notes Approved Most recent IF: 6.4  
  Call Number UA @ admin @ c:irua:189666 Serial 7082  
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Author Paulus, A.; Hendrickx, M.; Mayda, S.; Batuk, M.; Reekmans, G.; von Holst, M.; Elen, K.; Abakumov, A.M.; Adriaensens, P.; Lamoen, D.; Partoens, B.; Hadermann, J.; Van Bael, M.K.; Hardy, A. pdf  url
doi  openurl
  Title Understanding the Activation of Anionic Redox Chemistry in Ti4+-Substituted Li2MnO3as a Cathode Material for Li-Ion Batteries Type A1 Journal Article
  Year 2023 Publication ACS applied energy materials Abbreviated Journal ACS Appl. Energy Mater.  
  Volume 6 Issue 13 Pages 6956-6971  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)  
  Abstract Layered Li-rich oxides, demonstrating both cationic and anionic redox chemistry being used as positive electrodes for Li-ion batteries,have raised interest due to their high specific discharge capacities exceeding 250 mAh/g. However, irreversible structural transformations triggered by anionic redox chemistry result in pronounced voltagefade (i.e., lowering the specific energy by a gradual decay of discharge potential) upon extended galvanostatic cycling. Activating or suppressing oxygen anionic redox through structural stabilization induced by redox-inactivecation substitution is a well-known strategy. However, less emphasishas been put on the correlation between substitution degree and theactivation/suppression of the anionic redox. In this work, Ti4+-substituted Li2MnO3 was synthesizedvia a facile solution-gel method. Ti4+ is selected as adopant as it contains no partially filled d-orbitals. Our study revealedthat the layered “honeycomb-ordered” C2/m structure is preserved when increasing the Ticontent to x = 0.2 in the Li2Mn1-x Ti (x) O-3 solidsolution, as shown by electron diffraction and aberration-correctedscanning transmission electron microscopy. Galvanostatic cycling hintsat a delayed oxygen release, due to an improved reversibility of theanionic redox, during the first 10 charge-discharge cyclesfor the x = 0.2 composition compared to the parentmaterial (x = 0), followed by pronounced oxygen redoxactivity afterward. The latter originates from a low activation energybarrier toward O-O dimer formation and Mn migration in Li2Mn0.8Ti0.2O3, as deducedfrom first-principles molecular dynamics (MD) simulations for the“charged” state. Upon lowering the Ti substitution to x = 0.05, the structural stability was drastically improvedbased on our MD analysis, stressing the importance of carefully optimizingthe substitution degree to achieve the best electrochemical performance.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001018266700001 Publication Date 2023-07-10  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 2574-0962 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 6.4 Times cited Open Access Not_Open_Access: Available from 24.12.2023  
  Notes Universiteit Hasselt, AUHL/15/2 – GOH3816N ; Russian Science Foundation, 20-43-01012 ; Fonds Wetenschappelijk Onderzoek, AUHL/15/2 – GOH3816N G040116N ; The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWO Vlaanderen and the Flemish Government-department EWI. Approved Most recent IF: 6.4; 2023 IF: NA  
  Call Number EMAT @ emat @c:irua:198160 Serial 8809  
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Author Kamminga, M.E.; Batuk, M.; Hadermann, J.; Clarke, S.J. pdf  url
doi  openurl
  Title Misfit phase (BiSe)1.10NbSe2 as the origin of superconductivity in niobium-doped bismuth selenide Type A1 Journal article
  Year 2020 Publication Communications Materials Abbreviated Journal Commun Mater  
  Volume 1 Issue 1 Pages 82  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Topological superconductivity is of great contemporary interest and has been proposed in doped Bi<sub>2</sub>Se<sub>3</sub>, in which electron-donating atoms such as Cu, Sr or Nb have been intercalated into the Bi<sub>2</sub>Se<sub>3</sub>structure. For Nb<sub><italic>x</italic></sub>Bi<sub>2</sub>Se<sub>3</sub>, with<italic>T</italic><sub>c</sub> ~ 3 K, it is assumed in the literature that Nb is inserted in the van der Waals gap. However, in this work an alternative origin for the superconductivity in Nb-doped Bi<sub>2</sub>Se<sub>3</sub>is established. In contrast to previous reports, it is deduced that Nb intercalation in Bi<sub>2</sub>Se<sub>3</sub>does not take place. Instead, the superconducting behaviour in samples of nominal composition Nb<sub><italic>x</italic></sub>Bi<sub>2</sub>Se<sub>3</sub>results from the (BiSe)<sub>1.10</sub>NbSe<sub>2</sub>misfit phase that is present in the sample as an impurity phase for small<italic>x</italic>(0.01 ≤ <italic>x</italic> ≤ 0.10) and as a main phase for large<italic>x</italic>(<italic>x</italic> = 0.50). The structure of this misfit phase is studied in detail using a combination of X-ray diffraction and transmission electron microscopy techniques.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000610580800001 Publication Date 2020-11-10  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 2662-4443 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access OpenAccess  
  Notes M.E.K. was supported by the Netherlands Organisation for Scientific Research (NWO, grant code 019.181EN.003). We also acknowledge support from the EPSRC (EP/ R042594/1, EP/P018874/1, EP/M020517/1) and the Leverhulme Trust (RPG-2018-377). J.H. acknowledges support from the University of Antwerp through BOF Grant No. 31445. We thank DLS Ltd for beam time (EE18786), Dr Clare Murray for assistance on I11 and Dr Jon Wade from the Department of Earth Sciences, University of Oxford for performing the SEM measurements. We also thank Dr Michal Dušak and Dr Václav Petřiček for their advice concerning the use of the Jana2006 software. Approved Most recent IF: NA  
  Call Number EMAT @ emat @c:irua:176116 Serial 6705  
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Author Vishwakarma, M.; Thota, N.; Karakulina, O.; Hadermann, J.; Mehta, B.R. url  doi
openurl 
  Title Role of graphene inter layer on the formation of the MoS2 – CZTS interface during growth Type P1 Proceeding
  Year 2018 Publication (icc-2017) Abbreviated Journal  
  Volume Issue Pages  
  Keywords P1 Proceeding; Electron microscopy for materials research (EMAT)  
  Abstract The growth of MoS2 layer near the Mo/CZTS interface during sulphurization process can have an impact on back contact cell parameters (series resistance and fill factor) depending upon the thickness or quality of MoS2. This study reports the dependence of the thickness of interfacial MoS2 layer on the growth of graphene at the interface between molybdenum back contact and deposited CZTS layer. The graphene layer reduces the accumulation of Zn/ZnS, Sn/SnO2 and formation of pores near the MoS2-CZTS interface. The use of graphene as interface layer can be potentially useful for improving the quality of Mo/MoS2/CZTS interface.  
  Address  
  Corporate Author Thesis  
  Publisher Amer inst physics Place of Publication Melville Editor  
  Language Wos 000436313003046 Publication Date 2018-05-09  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume 1953 Series Issue Edition  
  ISSN (up) 978-0-7354-1648-2; 0094-243x; 0094-243x ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 1 Open Access OpenAccess  
  Notes ; The authors acknowledge support provided by DST project. M.V. acknowledges IIT Delhi for MHRD fellowship. Prof. B. R. Mehta acknowledges the support of the Schlumberger chair professorship. ; Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:153203 Serial 5126  
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Author Brammertz, G.; Buffiere, M.; Verbist, C.; Bekaert, J.; Batuk, M.; Hadermann, J.; et al. openurl 
  Title Process variability in Cu2ZnSnSe4 solar cell devices: Electrical and structural investigations Type P1 Proceeding
  Year 2015 Publication The conference record of the IEEE Photovoltaic Specialists Conference T2 – IEEE 42nd Photovoltaic Specialist Conference (PVSC), JUN 14-19, 2015, New Orleans, LA Abbreviated Journal  
  Volume Issue Pages  
  Keywords P1 Proceeding; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)  
  Abstract We have fabricated 9.7% efficient Cu2ZnSnSe4/CdS/ZnO solar cells by H2Se selenization of sequentially sputtered metal layers. Despite the good efficiency obtained, process control appears to be difficult. In the present contribution we compare the electrical and physical properties of two devices with nominal same fabrication procedure, but 1% and 9.7% power conversion efficiency respectively. We identify the problem of the lower performing device to be the segregation of ZnSe phases at the backside of the sample. This ZnSe seems to be the reason for the strong bias dependent photocurrent observed in the lower performing devices, as it adds a potential barrier for carrier collection. The reason for the different behavior of the two nominally same devices is not fully understood, but speculated to be related to sputtering variability.  
  Address  
  Corporate Author Thesis  
  Publisher Ieee Place of Publication New york Editor  
  Language Wos Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 978-1-4799-7944-8 ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:132335 Serial 4229  
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