Home | << 1 2 3 4 5 >> |
Records | |||||
---|---|---|---|---|---|
Author | Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D. | ||||
Title | First-principles study of the optoelectronic properties and photovoltaic absorber layer efficiency of Cu-based chalcogenides | Type | A1 Journal article | ||
Year | 2016 | Publication | Journal of applied physics | Abbreviated Journal | J Appl Phys |
Volume | 120 | Issue | 120 | Pages | 085707 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | Cu-based chalcogenides are promising materials for thin-film solar cells with more than 20% measured cell efficiency. Using first-principles calculations based on density functional theory, the optoelectronic properties of a group of Cu-based chalcogenides Cu2-II-IV-VI4 is studied. They are then screened with the aim of identifying potential absorber materials for photovoltaic applications. The spectroscopic limited maximum efficiency (SLME) introduced by Yu and Zunger [Phys. Rev. Lett. 108, 068701 (2012)] is used as a metric for the screening. After constructing the currentvoltage curve, the SLME is calculated from the maximum power output. The role of the nature of the band gap, direct or indirect, and also of the absorptivity of the studied materials on the maximum theoretical power conversion efficiency is studied. Our results show that Cu2II-GeSe4 with II¼ Cd and Hg, and Cu2-II-SnS4 with II ¼ Cd, Hg, and Zn have a higher theoretical efficiency compared with the materials currently used as absorber layer. |
||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000383913400074 | Publication Date | 2016-08-30 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0021-8979 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.068 | Times cited | 29 | Open Access | |
Notes | We acknowledge the financial support from the FWO-Vlaanderen through project G.0150.13N and a GOA fund from the University of Antwerp. 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), bothfunded by the FWO-Vlaanderen and the Flemish Government–department EWI. | Approved | Most recent IF: 2.068 | ||
Call Number | c:irua:135089 | Serial | 4113 | ||
Permanent link to this record | |||||
Author | Matsubara, M.; Saniz, R.; Partoens, B.; Lamoen, D. | ||||
Title | Doping anatase TiO2with group V-b and VI-b transition metal atoms: a hybrid functional first-principles study | Type | A1 Journal article | ||
Year | 2017 | Publication | Physical chemistry, chemical physics | Abbreviated Journal | Phys Chem Chem Phys |
Volume | 19 | Issue | 19 | Pages | 1945-1952 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | We investigate the role of transition metal atoms of group V-b (V, Nb, Ta) and VI-b (Cr, Mo, W) as n- or p-type dopants in anatase TiO$2$ using thermodynamic principles and density functional theory with the Heyd-Scuseria-Ernzerhof HSE06 hybrid functional. The HSE06 functional provides a realistic value for the band gap, which ensures a correct classification of dopants as shallow or deep donors or acceptors. Defect formation energies and thermodynamic transition levels are calculated taking into account the constraints imposed by the stability of TiO$2$ and the solubility limit of the impurities. Nb, Ta, W and Mo are identified as shallow donors. Although W provides two electrons, Nb and Ta show a considerable lower formation energy, in particular under O-poor conditions. Mo donates in principle one electron, but under specific conditions can turn into a double donor. V impurities are deep donors and Cr shows up as an amphoteric defect, thereby acting as an electron trapping center in n-type TiO$_2$ especially under O-rich conditions. A comparison with the available experimental data yields excellent agreement. |
||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000394426400027 | Publication Date | 2016-12-12 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1463-9076 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 4.123 | Times cited | 19 | Open Access | OpenAccess |
Notes | We gratefully acknowledge financial support from the IWTVlaanderenthrough projects G.0191.08 and G.0150.13, and the BOF-NOI of the University of Antwerp. This work was carried out using the HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC, which is funded by the Hercules foundation. M. M. acknowledges financial support from the GOA project ‘‘XANES meets ELNES’’ of the University of Antwerp. | Approved | Most recent IF: 4.123 | ||
Call Number | EMAT @ emat @ c:irua:140835 | Serial | 4421 | ||
Permanent link to this record | |||||
Author | Schouteden, K.; Govaerts, K.; Debehets, J.; Thupakula, U.; Chen, T.; Li, Z.; Netsou, A.; Song, F.; Lamoen, D.; Van Haesendonck, C.; Partoens, B.; Park, K. | ||||
Title | Annealing-Induced Bi Bilayer on Bi2Te3 Investigated via Quasi-Particle-Interference Mapping | Type | A1 Journal article | ||
Year | 2016 | Publication | ACS nano | Abbreviated Journal | Acs Nano |
Volume | 10 | Issue | 10 | Pages | 8778-8787 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | Topological insulators (TIs) are renowned for their exotic topological surface states (TSSs) that reside in the top atomic layers, and hence, detailed knowledge of the surface top atomic layers is of utmost importance. Here we present the remarkable morphology changes of Bi2Te3 surfaces, which have been freshly cleaved in air, upon subsequent systematic annealing in ultrahigh vacuum and the resulting effects on the local and area-averaging electronic properties of the surface states, which are investigated by combining scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), and Auger electron spectroscopy (AES) experiments with density functional theory (DFT) calculations. Our findings demonstrate that the annealing induces the formation of a Bi bilayer atop the Bi2Te3 surface. The adlayer results in n-type doping, and the atomic defects act as scattering centers of the TSS electrons. We also investigated the annealing-induced Bi bilayer surface on Bi2Te3 via voltage-dependent quasi-particle-interference (QPI) mapping of the surface local density of states and via comparison with the calculated constant-energy contours and QPI patterns. We observed closed hexagonal patterns in the Fourier transform of real-space QPI maps with secondary outer spikes. DFT calculations attribute these complex QPI patterns to the appearance of a “second” cone due to the surface charge transfer between the Bi bilayer and the Bi2Te3. Annealing in ultrahigh vacuum offers a facile route for tuning of the topological properties and may yield similar results for other topological materials. | ||||
Address | Department of Physics, Virginia Tech , Blacksburg, Virginia 24061, United States | ||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | English | Wos | 000384399300073 | Publication Date | 2016-09-02 |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1936-0851 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 13.942 | Times cited | 15 | Open Access | |
Notes | The research in Leuven and Antwerp was supported by the Research FoundationFlanders (FWO, Belgium). The research in Leuven received additional support from the Flemish Concerted Research Action Program (BOF KULeuven, Project GOA/14/007) and the KULeuven Project GOA “Fundamental Challenges in Semiconductor Research”. Z.L. acknowledges the support from the China Scholarship Council (2011624021) and from KU Leuven Internal Funds (PDM). K.S. and J.D. acknowledge additional support from the FWO. T.C. and F.S. acknowledge the financial support of the National Key Projects for Basic Research of China (Grants 2013CB922103 and 2011CB922103), the National NaturalScience Foundation of China (Grant s 91421109, 11134005,11522432, and 11274003), the Natural Science Foundation ofJiangsu Province (Grant BK20130054), and the FundamentalResearch Funds for the Central Universities. K.P. wassupported by the U.S. National Science Foundation (DMR-1206354) and San Diego Supercomputer Center (SDSC)Comet and Gordon (DMR060009N). | Approved | Most recent IF: 13.942 | ||
Call Number | EMAT @ emat @ c:irua:136269 | Serial | 4294 | ||
Permanent link to this record | |||||
Author | Jacobs, W.; Reynaerts, C.; Andries, S.; van den Akker, S.; Moonen, N.; Lamoen, D. | ||||
Title | Analyzing the dispersion of cargo vapors around a ship’s superstructure by means of wind tunnel experiments | Type | A1 Journal article | ||
Year | 2016 | Publication | Journal of marine science and technology | Abbreviated Journal | J Mar Sci Tech-Japan |
Volume | 21 | Issue | 21 | Pages | 758-766 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | In a previous study, it was found that cargo tank operations like cleaning and venting, lead to higher cargo vapor concentrations around the ship’s superstructure. Can wind tunnel experiments confirm these findings? Is there an improvement when using higher outlets at high velocities compared to lower outlets with a low outlet velocity? Is there a relation between relative wind speed and measured concentration? These questions were investigated in the Peutz wind tunnel. By using a tracer gas for the wind tunnel experiments, concentration coefficients have been calculated for various settings. The study shows that using high-velocity outlets is an efficient way to keep concentrations as low as possible. The only exception is for relative wind directions from the bow. In this last case using a manhole as ventilation outlet leads to lower concentrations. With increasing wind speeds the building downwash effect resulted in higher concentration coefficients near the main deck. This study confirms our on-board measurements and suggests the lowering of the ventilation inlet of the accommodation, so that the high-velocity outlet can be used safely at all times. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000388260200015 | Publication Date | 2016-05-21 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0948-4280 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 0.838 | Times cited | 2 | Open Access | |
Notes | The authors would like to thank Peutz bv. at Molenhoek, the Netherlands, for providing the wind tunnel facilities and their assistance during the various stages of this research. | Approved | Most recent IF: 0.838 | ||
Call Number | EMAT @ emat @ c:irua:138728 | Serial | 4326 | ||
Permanent link to this record | |||||
Author | Willhammar, T.; Sentosun, K.; Mourdikoudis, S.; Goris, B.; Kurttepeli, M.; Bercx, M.; Lamoen, D.; Partoens, B.; Pastoriza-Santos, I.; Pérez-Juste, J.; Liz-Marzán, L.M.; Bals, S.; Van Tendeloo, G. | ||||
Title | Structure and vacancy distribution in copper telluride nanoparticles influence plasmonic activity in the near-infrared | Type | A1 Journal article | ||
Year | 2017 | Publication | Nature communications | Abbreviated Journal | Nat Commun |
Volume | 8 | Issue | 8 | Pages | 14925 |
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | Copper chalcogenides find applications in different domains including photonics, photothermal therapy and photovoltaics. CuTe nanocrystals have been proposed as an alternative to noble metal particles for plasmonics. Although it is known that deviations from stoichiometry are a prerequisite for plasmonic activity in the near-infrared, an accurate description of the material and its (optical) properties is hindered by an insufficient understanding of the atomic structure and the influence of defects, especially for materials in their nanocrystalline form. We demonstrate that the structure of Cu1.5±xTe nanocrystals canbe determined using electron diffraction tomography. Real-space high-resolution electron tomography directly reveals the three-dimensional distribution of vacancies in the structure. Through first-principles density functional theory, we furthermore demonstrate that the influence of these vacancies on the optical properties of the nanocrystals is determined. Since our methodology is applicable to a variety of crystalline nanostructured materials, it is expected to provide unique insights concerning structure–property correlations. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000397799700001 | Publication Date | 2017-03-30 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2041-1723 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 12.124 | Times cited | 37 | Open Access | OpenAccess |
Notes | The work was financially supported by the European Research Council through an ERC Starting Grant (#335078-COLOURATOMS). T.W. acknowledges the Swedish Research Council for an international postdoc grant. We acknowledge financial support of FWO-Vlaanderen through project G.0216.14N, G.0369.15N and a postdoctoral research grant to B.G. 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. The work was further supported by the Spanish MINECO (MAT2013-45168-R). S.M. thanks the Action ooSupporting Postdoctoral Researchers44 of the Operational Program ‘Education and Lifelong Learning’ (Action’s Beneficiary: General Secretariat for Research and Technology of Greece), which was co-financed by the European Social Fund (ESF) and the Greek State. (ROMEO:green; preprint:; postprint:can ; pdfversion:can); ECAS_Sara | Approved | Most recent IF: 12.124 | ||
Call Number | EMAT @ emat @ c:irua:142203UA @ admin @ c:irua:142203 | Serial | 4538 | ||
Permanent link to this record | |||||
Author | Saniz, R.; Bekaert, J.; Partoens, B.; Lamoen, D. | ||||
Title | Structural and electronic properties of defects at grain boundaries in CuInSe2 | Type | A1 Journal article | ||
Year | 2017 | Publication | Physical chemistry, chemical physics | Abbreviated Journal | Phys Chem Chem Phys |
Volume | 19 | Issue | 19 | Pages | 14770-14780 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | We report on a first-principles study of the structural and electronic properties of a Sigma3 (112) grain boundary model in CuInSe2. The study focuses on a coherent, stoichiometry preserving, cation–Se terminated grain boundary, addressing the properties of the grain boundary as such, as well as the effect of well known defects in CuInSe2. We show that in spite of its apparent simplicity, such a grain boundary exhibits a very rich phenomenology, providing an explanation for several of the experimentally observed properties of grain boundaries in CuInSe2 thin films. In particular, we show that the combined effect of Cu vacancies and cation antisites can result in the observed Cu depletion with no In enrichment at the grain boundaries. Furthermore, Cu vacancies are unlikely to produce a hole barrier at the grain boundaries, but Na may indeed have such an effect. We find that Na-on-Cu defects will tend to form abundantly at the grain boundaries, and can provide a mechanism for the carrier depletion and/or type inversion experimentally reported. |
||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000403327200059 | Publication Date | 2017-05-12 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1463-9076 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 4.123 | Times cited | 12 | Open Access | OpenAccess |
Notes | We thank B. Schoeters for his assistance running the GBstudio software. We acknowledge the financial support of FWO-Vlaanderen through project G.0150.13. 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 FWO-Vlaanderen and the Flemish Government-department EWI. | Approved | Most recent IF: 4.123 | ||
Call Number | EMAT @ emat @ c:irua:143869 | Serial | 4577 | ||
Permanent link to this record | |||||
Author | Momot, A.; Amini, M.N.; Reekmans, G.; Lamoen, D.; Partoens, B.; Slocombe, D.R.; Elen, K.; Adriaensens, P.; Hardy, A.; Van Bael, M.K. | ||||
Title | A novel explanation for the increased conductivity in annealed Al-doped ZnO: an insight into migration of aluminum and displacement of zinc | Type | A1 Journal article | ||
Year | 2017 | Publication | Physical chemistry, chemical physics | Abbreviated Journal | Phys Chem Chem Phys |
Volume | 19 | Issue | 40 | Pages | 27866-27877 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
Abstract | A combined experimental and first-principles study is performed to study the origin of conductivity in ZnO:Al nanoparticles synthesized under controlled conditions via a reflux route using benzylamine as a solvent. The experimental characterization of the samples by Raman, nuclear magnetic resonance (NMR) and conductivity measurements indicates that upon annealing in nitrogen, the Al atoms at interstitial positions migrate to the substitutional positions, creating at the same time Zn interstitials. We provide evidence for the fact that the formed complex of AlZn and Zni corresponds to the origin of the Knight shifted peak (KS) we observe in 27Al NMR. As far as we know, the role of this complex has not been discussed in the literature to date. However, our first-principles calculations show that such a complex is indeed energetically favoured over the isolated Al interstitial positions. In our calculations we also address the charge state of the Al interstitials. Further, Zn interstitials can migrate from Al_Zn and possibly also form Zn clusters, leading to the observed increased conductivity. |
||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000413290500073 | Publication Date | 2017-10-09 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1463-9076 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 4.123 | Times cited | 26 | Open Access | OpenAccess |
Notes | We want to thank the Interuniversity Attraction Poles Programme (P7/05) initiated by the Belgian Science Policy Office (BELSPO) for the financial support. We also acknowledge the Research Foundation Flanders (FWO-Vlaanderen) for support via the MULTIMAR WOG project and under project No. G018914. The computational parts were carried out using the HPC infrastructure at the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC, supported financially by the Hercules foundation and the Flemish Government (EWI Department). | Approved | Most recent IF: 4.123 | ||
Call Number | EMAT @ emat @c:irua:146878 | Serial | 4760 | ||
Permanent link to this record | |||||
Author | Bercx, M.; Partoens, B.; Lamoen, D. | ||||
Title | Quantitative modeling of secondary electron emission from slow-ion bombardment on semiconductors | Type | A1 Journal article | ||
Year | 2019 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
Volume | 99 | Issue | 8 | Pages | 085413 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | When slow ions incident on a surface are neutralized, the excess potential energy is passed on to an electron inside the surface, leading to emission of secondary electrons. The microscopic description of this process, as well as the calculation of the secondary electron yield, is a challenging problem due to its complexity as well as its sensitivity to surface properties. One of the first quantitative descriptions was articulated in the 1950s by Hagstrum, who based his calculation on a parametrization of the density of states of the material. In this paper, we present a model for calculating the secondary electron yield, derived from Hagstrum’s initial approach. We use first-principles density functional theory calculations to acquire the necessary input and introduce the concept of electron cascades to Hagstrum’s model in order to improve the calculated spectra, as well as remove its reliance on fitting parameters. We apply our model to He+ and Ne+ ions incident on Ge(111) and Si(111) and obtain yield spectra that match closely to the experimental results of Hagstrum. |
||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000458367800010 | Publication Date | 2019-02-11 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 5 | Open Access | OpenAccess |
Notes | We would like to thank Prof. D. Depla for the useful discussions on the secondary electron yield. Furthermore, we acknowledge financial support of FWO-Vlaanderen through project G.0216.14N. 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 FWOVlaanderen and the Flemish Government-department EWI. | Approved | Most recent IF: 3.836 | ||
Call Number | EMAT @ emat @UA @ admin @ c:irua:157174 | Serial | 5154 | ||
Permanent link to this record | |||||
Author | Saniz, R.; Sarmadian, N.; Partoens, B.; Batuk, M.; Hadermann, J.; Marikutsa, A.; Rumyantseva, M.; Gaskov, A.; Lamoen, D. | ||||
Title | First-principles study of CO and OH adsorption on in-doped ZnO surfaces | Type | A1 Journal article | ||
Year | 2019 | Publication | The journal of physics and chemistry of solids | Abbreviated Journal | J Phys Chem Solids |
Volume | 132 | Issue | Pages | 172-181 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | We present a first-principles computational study of CO and OH adsorption on non-polar ZnO (10¯10) surfaces doped with indium. The calculations were performed using a model ZnO slab. The position of the In dopants was varied from deep bulk-like layers to the surface layers. It was established that the preferential location of the In atoms is at the surface by examining the dependence of the defect formation energy as well as the surface energy on In location. The adsorption sites on the surface of ZnO and the energy of adsorption of CO molecules and OH-species were determined in connection to In doping. It was found that OH has higher bonding energy to the surface than CO. The presence of In atoms at the surface of ZnO is favorable for CO adsorption, resulting in an elongation of the C-O bond and in charge transfer to the surface. The effect of CO and OH adsorption on the electronic and conduction properties of surfaces was assessed. We conclude that In-doped ZnO surfaces should present a higher electronic response upon adsorption of CO. |
||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000472124700023 | Publication Date | 2019-04-25 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-3697 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.059 | Times cited | 7 | Open Access | Not_Open_Access: Available from 26.04.2021 |
Notes | FWO-Vlaanderen, G0D6515N ; ERA.Net RUS Plus, 096 ; VSC; HPC infrastructure of the University of Antwerp; FWO-Vlaanderen; Flemish Government-department EWI; | Approved | Most recent IF: 2.059 | ||
Call Number | EMAT @ emat @UA @ admin @ c:irua:159656 | Serial | 5170 | ||
Permanent link to this record | |||||
Author | Bercx, M.; Slap, L.; Partoens, B.; Lamoen, D. | ||||
Title | First-Principles Investigation of the Stability of the Oxygen Framework of Li-Rich Battery Cathodes | Type | A1 Journal article | ||
Year | 2019 | Publication | MRS advances | Abbreviated Journal | MRS Adv. |
Volume | 4 | Issue | 14 | Pages | 813-820 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | Lithium-rich layered oxides such as Li<sub>2</sub>MnO<sub>3</sub>have shown great potential as cathodes in Li-ion batteries, mainly because of their large capacities. However, these materials still suffer from structural degradation as the battery is cycled, reducing the average voltage and capacity of the cell. The voltage fade is believed to be related to the migration of transition metals into the lithium layer, linked to the formation of O-O dimers with a short bond length, which in turn is driven by the presence of oxygen holes due to the participation of oxygen in the redox process. We investigate the formation of O-O dimers for partially charged O1-Li<sub>2</sub>MnO<sub>3</sub>using a first-principles density functional theory approach by calculating the reaction energy and kinetic barriers for dimer formation. Next, we perform similar calculations for partially charged O1-Li<sub>2</sub>IrO<sub>3</sub>, a Li-rich material for which the voltage fade was not observed during cycling. When we compare the stability of the oxygen framework, we conclude that the formation of O-O dimers is both thermodynamically and kinetically viable for O1-Li<sub>0.5</sub>MnO<sub>3</sub>. For O1-Li<sub>0.5</sub>IrO<sub>3</sub>, we observe that the oxygen lattice is much more stable, either returning to its original state when perturbed, or resulting in a structure with an O-O dimer that is much higher in energy. This can be explained by the mixed redox process for Li<sub>2</sub>IrO<sub>3</sub>, which is also shown from the calculated magnetic moments. The lack of O-O dimer formation in O1-Li<sub>0.5</sub>IrO<sub>3</sub>provides valuable insight as to why Li<sub>2</sub>IrO<sub>3</sub>does not demonstrate a voltage fade as the battery is cycled, which can be used to design Li-rich battery cathodes with an improved cycling performance. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000466846700004 | Publication Date | 2019-02-21 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2059-8521 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | Times cited | 3 | Open Access | Not_Open_Access: Available from 22.02.2020 | |
Notes | We acknowledge the financial support of FWO-Vlaanderen through project 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: NA | ||
Call Number | EMAT @ emat @UA @ admin @ c:irua:160121 | Serial | 5179 | ||
Permanent link to this record | |||||
Author | Choudhary, K.; Bercx, M.; Jiang, J.; Pachter, R.; Lamoen, D.; Tavazza, F. | ||||
Title | Accelerated Discovery of Efficient Solar Cell Materials Using Quantum and Machine-Learning Methods | Type | A1 Journal article | ||
Year | 2019 | Publication | Chemistry of materials | Abbreviated Journal | Chem Mater |
Volume | 31 | Issue | 15 | Pages | 5900-5908 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Solar energy plays an important role in solving serious environmental problems and meeting the high energy demand. However, the lack of suitable materials hinders further progress of this technology. Here, we present the largest inorganic solar cell material search till date using density functional theory (DFT) and machine-learning approaches. We calculated the spectroscopic limited maximum efficiency (SLME) using the Tran−Blaha-modified Becke−Johnson potential for 5097 nonmetallic materials and identified 1997 candidates with an SLME higher than 10%, including 934 candidates with a suitable convex-hull stability and an effective carrier mass. Screening for two-dimensional-layered cases, we found 58 potential materials and performed G0W0 calculations on a subset to estimate the prediction uncertainty. As the above DFT methods are still computationally expensive, we developed a high accuracy machine-learning model to prescreen efficient materials and applied it to over a million materials. Our results provide a general framework and universal strategy for the design of high-efficiency solar cell materials. The data and tools are publicly distributed at: https://www.ctcms.nist.gov/~knc6/JVASP.html, https://www. ctcms.nist.gov/jarvisml/, https://jarvis.nist.gov/, and https://github.com/usnistgov/jarvis. |
||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000480826900060 | Publication Date | 2019-08-13 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0897-4756 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 9.466 | Times cited | 6 | Open Access | |
Notes | ; ; | Approved | Most recent IF: 9.466 | ||
Call Number | EMAT @ emat @c:irua:161814 | Serial | 5291 | ||
Permanent link to this record | |||||
Author | Callaert, C.; Bercx, M.; Lamoen, D.; Hadermann, J. | ||||
Title | Interstitial defects in the van der Waals gap of Bi2Se3 | Type | A1 Journal article | ||
Year | 2019 | Publication | Acta Crystallographica. Section B: Structural Science, Crystal Engineering and Materials (Online) | Abbreviated Journal | Acta Crystallogr B |
Volume | 75 | Issue | 4 | Pages | 717-732 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Bi<sub>2</sub>Se<sub>3</sub>is a thermoelectric material and a topological insulator. It is slightly conducting in its bulk due to the presence of defects and by controlling the defects different physical properties can be fine tuned. However, studies of the defects in this material are often contradicting or inconclusive. Here, the defect structure of Bi<sub>2</sub>Se<sub>3</sub>is studied with a combination of techniques: high-resolution scanning transmission electron microscopy (HR-STEM), high-resolution energy-dispersive X-ray (HR-EDX) spectroscopy, precession electron diffraction tomography (PEDT), X-ray diffraction (XRD) and first-principles calculations using density functional theory (DFT). Based on these results, not only the observed defects are discussed, but also the discrepancies in results or possibilities across the techniques. STEM and EDX revealed interstitial defects with mainly Bi character in an octahedral coordination in the van der Waals gap, independent of the applied sample preparation method (focused ion beam milling or cryo-crushing). The inherent character of these defects is supported by their observation in the structure refinement of the EDT data. Moreover, the occupancy probability of the defects determined by EDT is inversely proportional to their corresponding DFT calculated formation energies. STEM also showed the migration of some atoms across and along the van der Waals gap. The kinetic barriers calculated using DFT suggest that some paths are possible at room temperature, while others are most probably beam induced. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000480512600024 | Publication Date | 2019-08-01 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2052-5206 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.032 | Times cited | Open Access | ||
Notes | University of Antwerp, 31445 ; Acknowledgements We thank Artem M. Abakumov for providing the original Bi2Se3 sample and are also very grateful to Christophe Vandevelde for trying repeatedly to get good single crystal X-ray diffraction data out of each of our failed attempts at making an undeformed single crystal. 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: 2.032 | ||
Call Number | EMAT @ emat @c:irua:161847 | Serial | 5295 | ||
Permanent link to this record | |||||
Author | Marchetti, A.; Saniz, R.; Krishnan, D.; Rabbachin, L.; Nuyts, G.; De Meyer, S.; Verbeeck, J.; Janssens, K.; Pelosi, C.; Lamoen, D.; Partoens, B.; De Wael, K. | ||||
Title | Unraveling the Role of Lattice Substitutions on the Stabilization of the Intrinsically Unstable Pb2Sb2O7Pyrochlore: Explaining the Lightfastness of Lead Pyroantimonate Artists’ Pigments | Type | A1 Journal article | ||
Year | 2020 | Publication | Chemistry Of Materials | Abbreviated Journal | Chem Mater |
Volume | 32 | Issue | 7 | Pages | 2863-2873 |
Keywords | A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | The pyroantimonate pigments Naples yellow and lead tin antimonate yellow are recognized as some of the most stable synthetic yellow pigments in the history of art. However, this exceptional lightfastness is in contrast with experimental evidence suggesting that this class of mixed oxides is of semiconducting nature. In this study the electronic structure and light-induced behavior of the lead pyroantimonate pigments were determined by means of a combined multifaceted analytical and computational approach (photoelectrochemical measurements, UV-vis diffuse reflectance spectroscopy, STEM-EDS, STEM-HAADF, and density functional theory calculations). The results demonstrate both the semiconducting nature and the lightfastness of these pigments. Poor optical absorption and minority carrier mobility are the main properties responsible for the observed stability. In addition, novel fundamental insights into the role played by Na atoms in the stabilization of the otherwise intrinsically unstable Pb2Sb2O7 pyrochlore were obtained. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000526394000016 | Publication Date | 2020-04-14 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0897-4756 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 8.6 | Times cited | 8 | Open Access | OpenAccess |
Notes | Universiteit Antwerpen; Belgian Federal Science Policy Office; | Approved | Most recent IF: 8.6; 2020 IF: 9.466 | ||
Call Number | EMAT @ emat @c:irua:168819 | Serial | 6363 | ||
Permanent link to this record | |||||
Author | Caglak, E.; Govers, K.; Lamoen, D.; Labeau, P.-E.; Verwerft, M. | ||||
Title | Atomic scale analysis of defect clustering and predictions of their concentrations in UO2+x | Type | A1 Journal article | ||
Year | 2020 | Publication | Journal Of Nuclear Materials | Abbreviated Journal | J Nucl Mater |
Volume | 541 | Issue | Pages | 152403 | |
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | The physical properties of uranium dioxide vary greatly with stoichiometry. Oxidation towards hyperstoichiometric UO2 – UO2+x – might be encountered at various stages of the nuclear fuel cycle if oxidative conditions are met; the impact of stoichiometry changes upon physical properties should therefore be properly assessed to ensure safe and reliable operations. These physical properties are intimately linked to the arrangement of atomic defects in the crystalline structure. The evolution of the defect concentration with environmental parameters – oxygen partial pressure and temperature – were evaluated by means of a point defect model where the reaction energies are derived from atomic-scale simulations. To this end, various configurations and net charge states of oxygen interstitial clusters in UO2 have been calculated. Various methodologies have been tested to determine the optimum cluster configurations and a rigid lattice approach turned out to be the most useful strategy to optimize defect configuration structures. Ultimately, results from the point defect model were discussed and compared to experimental measurements of stoichiometry dependence on oxygen partial pressure and temperature. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000575165800006 | Publication Date | 2020-08-06 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-3115 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.1 | Times cited | Open Access | OpenAccess | |
Notes | This work is dedicated to the memory of Prof. Alain Dubus, ULB, Bruxelles, Belgium. Financial support from the SCK CEN is gratefully acknowledged. | Approved | Most recent IF: 3.1; 2020 IF: 2.048 | ||
Call Number | EMAT @ emat @c:irua:172464 | Serial | 6402 | ||
Permanent link to this record | |||||
Author | Saniz, R.; Bekaert, J.; Partoens, B.; Lamoen, D. | ||||
Title | First-principles study of defects at Σ3 grain boundaries in CuGaSe2 | Type | A1 Journal article | ||
Year | 2021 | Publication | Solid State Communications | Abbreviated Journal | Solid State Commun |
Volume | Issue | Pages | 114263 | ||
Keywords | A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT) | ||||
Abstract | We present a first-principles computational study of cation–Se 3 (112) grain boundaries in CuGaSe. We discuss the structure of these grain boundaries, as well as the effect of native defects and Na impurities on their electronic properties. The formation energies show that the defects will tend to form preferentially at the grain boundaries, rather than in the grain interiors. We find that in Ga-rich growth conditions Cu vacancies as well as Ga at Cu and Cu at Ga antisites are mainly responsible for having the equilibrium Fermi level pinned toward the middle of the gap, resulting in carrier depletion. The Na at Cu impurity in its +1 charge state contributes to this. In Ga-poor growth conditions, on the other hand, the formation energies of Cu vacancies and Ga at Cu antisites are comparatively too high for any significant influence on carrier density or on the equilibrium Fermi level position. Thus, under these conditions, the Cu at Ga antisites give rise to a -type grain boundary. Also, their formation energy is lower than the formation energy of Na at Cu impurities. Thus, the latter will fail to act as a hole barrier preventing recombination at the grain boundary, in contrast to what occurs in CuInSe grain boundaries. We also discuss the effect of the defects on the electronic properties of bulk CuGaSe, which we assume reflect the properties of the grain interiors. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000652668500013 | Publication Date | 2021-03-12 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0038-1098 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 1.554 | Times cited | 1 | Open Access | OpenAccess |
Notes | Fwo; We acknowledge the financial support of FWO-Vlaanderen, Belgium through project G.0150.13. 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 FWO-Vlaanderen and the Flemish Government-department EWI. | Approved | Most recent IF: 1.554 | ||
Call Number | EMAT @ emat @c:irua:176544 | Serial | 6703 | ||
Permanent link to this record | |||||
Author | Leinders, G.; Baldinozzi, G.; Ritter, C.; Saniz, R.; Arts, I.; Lamoen, D.; Verwerft, M. | ||||
Title | Charge Localization and Magnetic Correlations in the Refined Structure of U3O7 | Type | A1 Journal article | ||
Year | 2021 | Publication | Inorganic Chemistry | Abbreviated Journal | Inorg Chem |
Volume | 60 | Issue | 14 | Pages | 10550-10564 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Atomic arrangements in the mixed-valence oxide U3O7 are refined from high-resolution neutron scattering data. The crystallographic model describes a long-range structural order in a U60O140 primitive cell (space group P42/n) containing distorted cuboctahedral oxygen clusters. By combining experimental data and electronic structure calculations accounting for spin–orbit interactions, we provide robust evidence of an interplay between charge localization and the magnetic moments carried by the uranium atoms. The calculations predict U3O7 to be a semiconducting solid with a band gap of close to 0.32 eV, and a more pronounced charge-transfer insulator behavior as compared to the well-known Mott insulator UO2. Most uranium ions (56 out of 60) occur in 9-fold and 10-fold coordinated environments, surrounding the oxygen clusters, and have a tetravalent (24 out of 60) or pentavalent (32 out of 60) state. The remaining uranium ions (4 out of 60) are not contiguous to the oxygen cuboctahedra and have a very compact, 8-fold coordinated environment with two short (2 × 1.93(3) Å) “oxo-type” bonds. The higher Hirshfeld charge and the diamagnetic character point to a hexavalent state for these four uranium ions. Hence, the valence state distribution corresponds to 24/60 × U(IV) + 32/60 U(V) + 4/60 U(VI). The tetravalent and pentavalent uranium ions are predicted to carry noncollinear magnetic moments (with amplitudes of 1.6 and 0.8 μB, respectively), resulting in canted ferromagnetic order in characteristic layers within the overall fluorite-related structure. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000675430900049 | Publication Date | 2021-07-19 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0020-1669 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 4.857 | Times cited | Open Access | OpenAccess | |
Notes | Financial support for this research was partly provided by the Energy Transition Fund of the Belgian FPS Economy (Project SF-CORMOD – Spent Fuel CORrosion MODeling). This work was performed in part using HPC resources from GENCI-IDRIS (Grants 2020-101450 and 2020-101601), and in part 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. GL thanks E. Suard and C. Schreinemachers for assistance during the neutron scattering experiments at the ILL. GB acknowledges V. Petříček for suggestions on using JANA2006. | Approved | Most recent IF: 4.857 | ||
Call Number | EMAT @ emat @c:irua:179907 | Serial | 6801 | ||
Permanent link to this record | |||||
Author | Nematollahi, P.; Barbiellini, B.; Bansil, A.; Lamoen, D.; Qingying, J.; Mukerjee, S.; Neyts, E.C. | ||||
Title | Identification of a Robust and Durable FeN4CxCatalyst for ORR in PEM Fuel Cells and the Role of the Fifth Ligand | Type | A1 Journal article | ||
Year | 2022 | Publication | ACS catalysis | Abbreviated Journal | Acs Catal |
Volume | Issue | Pages | 7541-7549 | ||
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
Abstract | Although recent studies have advanced the understanding of pyrolyzed Fe−N−C materials as oxygen reduction reaction (ORR) catalysts, the atomic and electronic structures of the active sites and their detailed reaction mechanisms still remain unknown. Here, based on first-principles density functional theory (DFT) computations, we discuss the electronic structures of three FeN4 catalytic centers with different local topologies of the surrounding C atoms with a focus on unraveling the mechanism of their ORR activity in acidic electrolytes. Our study brings back a forgotten, synthesized pyridinic Fe−N coordinate to the community’s attention, demonstrating that this catalyst can exhibit excellent activity for promoting direct four-electron ORR through the addition of a fifth ligand such as −NH2, −OH, and −SO4. We also identify sites with good stability properties through the combined use of our DFT calculations and Mössbauer spectroscopy data. |
||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000823193100001 | Publication Date | 2022-06-10 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2155-5435 | ISBN | Additional Links | UA library record; WoS full record; WoS full record; WoS citing articles | |
Impact Factor | 12.9 | Times cited | Open Access | OpenAccess | |
Notes | Basic Energy Sciences, DE-FG02-07ER46352 ; Fonds Wetenschappelijk Onderzoek, 1261721N ; Opetus- ja Kulttuuriministeri?; Department of Energy, DE-EE0008416 ; | Approved | Most recent IF: 12.9 | ||
Call Number | EMAT @ emat @c:irua:189000 | Serial | 7073 | ||
Permanent link to this record | |||||
Author | Saniz, R.; Baldinozzi, G.; Arts, I.; Lamoen, D.; Leinders, G.; Verwerft, M. | ||||
Title | Charge order, frustration relief, and spin-orbit coupling in U3O8 | Type | A1 Journal article | ||
Year | 2023 | Publication | Physical review materials | Abbreviated Journal | |
Volume | 7 | Issue | 5 | Pages | 054410 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Research efforts on the description of the low-temperature magnetic order and electronic properties of U3O8 have been inconclusive so far. Reinterpreting neutron scattering results, we use group representation theory to show that the ground state presents collinear out-of-plane magnetic moments, with antiferromagnetic coupling both in-layer and between layers. Charge order relieves the initial geometric frustration, generating a slightly distorted honeycomb sublattice with Néel-type order. The precise knowledge of the characteristics of this magnetic ground state is then used to explain the fine features of the band gap. In this system, spin-orbit coupling (SOC) is of critical importance, as it strongly affects the electronic structure, narrowing the gap by ∼38%, compared to calculations neglecting SOC. The predicted electronic structure actually explains the salient features of recent optical absorption measurements, further demonstrating the excellent agreement between the calculated ground state properties and experiment. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 001041429800007 | Publication Date | 2023-05-31 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2475-9953 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 3.4 | Times cited | Open Access | OpenAccess | |
Notes | Financial support for this research was partly provided by the Energy Transition Fund of the Belgian FPS Economy (Project SF-CORMOD Spent Fuel CORrosion MODeling).Fonds Wetenschappelijk Onderzoek; Vlaams Supercomputer Centrum; Universiteit Antwerpen; Vlaamse regering; | Approved | Most recent IF: 3.4; 2023 IF: NA | ||
Call Number | EMAT @ emat @c:irua:197043 | Serial | 8796 | ||
Permanent link to this record | |||||
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. | ||||
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 | 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 | ||
Permanent link to this record | |||||
Author | Bercx, M.; Mayda, S.; Depla, D.; Partoens, B.; Lamoen, D. | ||||
Title | Plasmonic effects in the neutralization of slow ions at a metallic surface | Type | A1 Journal Article | ||
Year | 2023 | Publication | Contributions to Plasma Physics | Abbreviated Journal | Contrib. Plasma Phys |
Volume | Issue | Pages | |||
Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
Abstract | Secondary electron emission is an important process that plays a significant role in several plasma‐related applications. As measuring the secondary electron yield experimentally is very challenging, quantitative modelling of this process to obtain reliable yield data is critical as input for higher‐scale simulations. Here, we build upon our previous work combining density functional theory calculations with a model originally developed by Hagstrum to extend its application to metallic surfaces. As plasmonic effects play a much more important role in the secondary electron emission mechanism for metals, we introduce an approach based on Poisson point processes to include both surface and bulk plasmon excitations to the process. The resulting model is able to reproduce the yield spectra of several available experimental results quite well but requires the introduction of global fitting parameters, which describe the strength of the plasmon interactions. Finally, we use an in‐house developed workflow to calculate the electron yield for a list of elemental surfaces spanning the periodic table to produce an extensive data set for the community and compare our results with more simplified approaches from the literature. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 001067651300001 | Publication Date | 2023-09-16 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0863-1042 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 1.6 | Times cited | Open Access | Not_Open_Access | |
Notes | We acknowledge the financial support of FWO-Vlaanderen through project G.0216.14N. 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: 1.6; 2023 IF: 1.44 | ||
Call Number | EMAT @ emat @c:irua:200330 | Serial | 8962 | ||
Permanent link to this record | |||||
Author | Claes, J.; Partoens, B.; Lamoen, D. | ||||
Title | Decoupled DFT-1/2 method for defect excitation energies | Type | A1 Journal Article | ||
Year | 2023 | Publication | Physical Review B | Abbreviated Journal | Phys. Rev. B |
Volume | 108 | Issue | 12 | Pages | 125306 |
Keywords | A1 Journal Article; Condensed Matter Theory (CMT) ; | ||||
Abstract | The DFT-1/2 method is a band-gap correction with GW precision at a density functional theory (DFT) computational cost. The method was also extended to correct the gap between defect levels, allowing for the calculation of optical transitions. However, this method fails when the atomic character of the occupied and unoccupied defect levels is similar as we illustrate by two examples, the tetrahedral hydrogen interstitial and the negatively charged vacancy in diamond. We solve this problem by decoupling the effect of the occupied and unoccupied defect levels and call this the decoupled DFT-1/2 method for defects. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 001089302800003 | Publication Date | 2023-09-25 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 3.7 | Times cited | Open Access | Not_Open_Access | |
Notes | This work was supported by the FWO (Research Foundation-Flanders), Project No. G0D1721N. This work was performed in part using HPC resources from 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 (Economie, Wetenschap & Innovatie). | Approved | Most recent IF: 3.7; 2023 IF: 3.836 | ||
Call Number | CMT @ cmt @c:irua:201287 | Serial | 8976 | ||
Permanent link to this record | |||||
Author | Schowalter, M.; Titantah, J.T.; Lamoen, D.; Kruse, P. | ||||
Title | Ab initio computation of the mean inner Coulomb potential of amorphous carbon structures | Type | A1 Journal article | ||
Year | 2005 | Publication | Applied physics letters | Abbreviated Journal | Appl Phys Lett |
Volume | 86 | Issue | Pages | 112102 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000228050700042 | Publication Date | 2005-03-04 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0003-6951; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.411 | Times cited | 15 | Open Access | |
Notes | Approved | Most recent IF: 3.411; 2005 IF: 4.127 | |||
Call Number | UA @ lucian @ c:irua:51764 | Serial | 31 | ||
Permanent link to this record | |||||
Author | Schowalter, M.; Rosenauer, A.; Lamoen, D.; Kruse, P.; Gerthsen, D. | ||||
Title | Ab initio computation of the mean inner Coulomb potential of wurtzite-type semiconductors and gold | Type | A1 Journal article | ||
Year | 2006 | Publication | Applied Physics Letters | Abbreviated Journal | Appl Phys Lett |
Volume | 88 | Issue | 23 | Pages | Artn 232108 |
Keywords | A1 Journal article; Electron Microscopy for Materials Science (EMAT); | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000238914500031 | Publication Date | 2006-06-19 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0003-6951; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.411 | Times cited | 8 | Open Access | |
Notes | Approved | Most recent IF: 3.411; 2006 IF: 3.977 | |||
Call Number | UA @ lucian @ c:irua:60581 | Serial | 33 | ||
Permanent link to this record | |||||
Author | Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D. | ||||
Title | Ab initio study of shallow acceptors in bixbyite V2O3 | Type | A1 Journal article | ||
Year | 2015 | Publication | Journal of applied physics | Abbreviated Journal | J Appl Phys |
Volume | 117 | Issue | 117 | Pages | 015703 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | We present the results of our study on p-type dopability of bixbyite V2O3 using the Heyd, Scuseria, and Ernzerhof hybrid functional (HSE06) within the density functional theory (DFT) formalism. We study vanadium and oxygen vacancies as intrinsic defects and substitutional Mg, Sc, and Y as extrinsic defects. We find that Mg substituting V acts as a shallow acceptor, and that oxygen vacancies are electrically neutral. Hence, we predict Mg-doped V2O3 to be a p-type conductor. Our results also show that vanadium vacancies are relatively shallow, with a binding energy of 0.14 eV, so that they might also lead to p-type conductivity. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000347958600067 | Publication Date | 2015-01-05 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0021-8979;1089-7550; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.068 | Times cited | 3 | Open Access | |
Notes | FWO G015013; Hercules | Approved | Most recent IF: 2.068; 2015 IF: 2.183 | ||
Call Number | c:irua:122728 | Serial | 35 | ||
Permanent link to this record | |||||
Author | Titantah, J.T.; Lamoen, D.; Schowalter, M.; Rosenauer, A. | ||||
Title | Bond length variation in Ga1-xInxAs crystals from the Tersoff potential | Type | A1 Journal article | ||
Year | 2007 | Publication | Journal of applied physics | Abbreviated Journal | J Appl Phys |
Volume | 101 | Issue | 12 | Pages | 123508,1-4 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000247625700034 | Publication Date | 2007-06-20 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0021-8979; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.068 | Times cited | 19 | Open Access | |
Notes | Approved | Most recent IF: 2.068; 2007 IF: 2.171 | |||
Call Number | UA @ lucian @ c:irua:67460 | Serial | 247 | ||
Permanent link to this record | |||||
Author | Schowalter, M.; Lamoen, D.; Kruse, P.; Gerthsen, D.; Rosenauer, A. | ||||
Title | First-principles calculations of the mean inner Coulomb potential for sphalerite type II.VI semiconductors | Type | A1 Journal article | ||
Year | 2004 | Publication | Applied Physics Letters | Abbreviated Journal | Appl Phys Lett |
Volume | 85 | Issue | 21 | Pages | 4938-4940 |
Keywords | A1 Journal article; Electron Microscopy for Materials Science (EMAT); | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000225300600037 | Publication Date | 2004-11-24 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0003-6951; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.411 | Times cited | 16 | Open Access | |
Notes | Approved | Most recent IF: 3.411; 2004 IF: 4.308 | |||
Call Number | UA @ lucian @ c:irua:49657 | Serial | 1203 | ||
Permanent link to this record | |||||
Author | Bekaert, J.; Saniz, R.; Partoens, B.; Lamoen, D. | ||||
Title | First-principles study of carbon impurities in CuInSe2 and CuGaSe2, present in non-vacuum synthesis methods | Type | A1 Journal article | ||
Year | 2015 | Publication | Journal of applied physics | Abbreviated Journal | J Appl Phys |
Volume | 117 | Issue | 117 | Pages | 015104 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | A first-principles study of the structural and electronic properties of carbon impurities in CuInSe2 and CuGaSe2 is presented. Carbon is present in organic molecules in the precursor solutions used in non-vacuum growth methods for CuInSe2 and CuGaSe2 based photovoltaic cells. These growth methods make more efficient use of material, time, and energy than traditional vacuum methods. The formation energies of several carbon impurities are calculated using the hybrid HSE06 functional. C Cu acts as a shallow donor, CIn and interstitial C yield deep donor levels in CuInSe2, while in CuGaSe2 CGa and interstitial C act as deep amphoteric defects. So, these defects reduce the majority carrier (hole) concentration in p-type CuInSe2 and CuGaSe2 by compensating the acceptor levels. The deep defects are likely to act as recombination centers for the photogenerated charge carriers and are thus detrimental for the performance of the photovoltaic cells. On the other hand, the formation energies of the carbon impurities are high, even under C-rich growth conditions. Thus, few C impurities will form in CuInSe2 and CuGaSe2 in thermodynamic equilibrium. However, the deposition of the precursor solution in non-vacuum growth methods presents conditions far from thermodynamic equilibrium. In this case, our calculations show that C impurities formed in non-equilibrium tend to segregate from CuInSe2 and CuGaSe2 by approaching thermodynamic equilibrium, e.g., via thorough annealing. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000347958600055 | Publication Date | 2015-01-07 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0021-8979;1089-7550; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.068 | Times cited | 6 | Open Access | |
Notes | FWO G015013; Hercules | Approved | Most recent IF: 2.068; 2015 IF: 2.183 | ||
Call Number | c:irua:122064 | Serial | 1215 | ||
Permanent link to this record | |||||
Author | Amini, M.N.; Saniz, R.; Lamoen, D.; Partoens, B. | ||||
Title | Hydrogen impurities and native defects in CdO | Type | A1 Journal article | ||
Year | 2011 | Publication | Journal of applied physics | Abbreviated Journal | J Appl Phys |
Volume | 110 | Issue | 6 | Pages | 063521,1-063521,7 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | We have used first-principles calculations based on density functional theory to study point defects in CdO within the local density approximation and beyond (LDA+U). Hydrogen interstitials and oxygen vacancies are found to act as shallow donors and can be interpreted as the cause of conductivity in CdO. Hydrogen can also occupy an oxygen vacancy in its substitutional form and also acts as a shallow donor. Similar to what was found for ZnO and MgO, hydrogen creates a multicenter bond with its six oxygen neighbors in CdO. The charge neutrality level for native defects and hydrogen impurities has been calculated. It is shown that in the case of native defects, it is not uniquely defined. Indeed, this level depends highly on the chemical potentials of the species and one can obtain different values for different end states in the experiment. Therefore, a comparison with experiment can only be made if the chemical potentials of the species in the experiment are well defined. However, for the hydrogen interstitial defect, since this level is independent of the chemical potential of hydrogen, one can obtain a unique value for the charge neutrality level. We find that the Fermi level stabilizes at 0.43 eV above the conduction band minimum in the case of the hydrogen interstitial defect, which is in good agreement with the experimentally reported value of 0.4 eV. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000295619300041 | Publication Date | 2011-09-23 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0021-8979; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.068 | Times cited | 13 | Open Access | |
Notes | ; The authors gratefully acknowledge financial support from the IWT-Vlaanderen through the ISIMADE project, the FWO-Vlaanderen through Project G.0191.08 and the BOF-NOI of the University of Antwerp. This work was carried out using the HPC infrastructure at the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC. ; | Approved | Most recent IF: 2.068; 2011 IF: 2.168 | ||
Call Number | UA @ lucian @ c:irua:93613 | Serial | 1533 | ||
Permanent link to this record | |||||
Author | Zhang, M.-L.; March, N.H.; Peeters, A.; van Alsenoy, C.; Howard, I.; Lamoen, D.; Leys, F. | ||||
Title | Loss rate of a plasticizer in a nylon matrix calculated using macroscopic reaction-diffusion kinetics | Type | A1 Journal article | ||
Year | 2003 | Publication | Journal Of Applied Physics | Abbreviated Journal | J Appl Phys |
Volume | 93 | Issue | Pages | 1525-1532 | |
Keywords | A1 Journal article; Electron Microscopy for Materials Science (EMAT); | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000180630200031 | Publication Date | 2003-02-10 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0021-8979; | ISBN | Additional Links | UA library record; WoS full record; | |
Impact Factor | 2.068 | Times cited | Open Access | ||
Notes | Approved | Most recent IF: 2.068; 2003 IF: 2.171 | |||
Call Number | UA @ lucian @ c:irua:41405 | Serial | 1844 | ||
Permanent link to this record | |||||
Author | Müller, E.; Kruse, P.; Gerthsen, D.; Schowalter, M.; Rosenauer, A.; Lamoen, D.; Kling, R.; Waag, A. | ||||
Title | Measurement of the mean inner potential of ZnO nanorods by transmission electron holography | Type | A1 Journal article | ||
Year | 2005 | Publication | Applied Physics Letters | Abbreviated Journal | Appl Phys Lett |
Volume | 86 | Issue | 15 | Pages | |
Keywords | A1 Journal article; Electron Microscopy for Materials Science (EMAT); | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000228901600121 | Publication Date | 2005-04-06 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0003-6951; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.411 | Times cited | 5 | Open Access | |
Notes | Approved | Most recent IF: 3.411; 2005 IF: 4.127 | |||
Call Number | UA @ lucian @ c:irua:54917 | Serial | 1963 | ||
Permanent link to this record |