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Bercx, M.; Mayda, S.; Depla, D.; Partoens, B.; Lamoen, D. |
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Title |
Plasmonic effects in the neutralization of slow ions at a metallic surface |
Type |
A1 Journal Article |
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Year  |
2023 |
Publication |
Contributions to Plasma Physics |
Abbreviated Journal |
Contrib. Plasma Phys |
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Keywords |
A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; |
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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. |
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Wos |
001067651300001 |
Publication Date |
2023-09-16 |
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Edition |
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ISSN |
0863-1042 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
1.6 |
Times cited |
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Open Access |
Not_Open_Access |
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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 |
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Call Number |
EMAT @ emat @c:irua:200330 |
Serial |
8962 |
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Author |
Paulus, A.; Hendrickx, M.; Bercx, M.; Karakulina, O.M.; Kirsanova, M.A.; Lamoen, D.; Hadermann, J.; Abakumov, A.M.; Van Bael, M.K.; Hardy, A. |
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Title |
An in-depth study of Sn substitution in Li-rich/Mn-rich NMC as a cathode material for Li-ion batteries |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Journal of the Chemical Society : Dalton transactions |
Abbreviated Journal |
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Volume |
49 |
Issue |
30 |
Pages |
10486-10497 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Layered Li-rich/Mn-rich NMC (LMR-NMC) is characterized by high initial specific capacities of more than 250 mA h g(-1), lower cost due to a lower Co content and higher thermal stability than LiCoO2. However, its commercialisation is currently still hampered by significant voltage fade, which is caused by irreversible transition metal ion migration to emptied Li positionsviatetrahedral interstices upon electrochemical cycling. This structural change is strongly correlated with anionic redox chemistry of the oxygen sublattice and has a detrimental effect on electrochemical performance. In a fully charged state, up to 4.8 Vvs.Li/Li+, Mn4+ is prone to migrate to the Li layer. The replacement of Mn4+ for an isovalent cation such as Sn4+ which does not tend to adopt tetrahedral coordination and shows a higher metal-oxygen bond strength is considered to be a viable strategy to stabilize the layered structure upon extended electrochemical cycling, hereby decreasing voltage fade. The influence of Sn4+ on the voltage fade in partially charged LMR-NMC is not yet reported in the literature, and therefore, we have investigated the structure and the corresponding electrochemical properties of LMR-NMC with different Sn concentrations. We determined the substitution limit of Sn4+ in Li1.2Ni0.13Co0.13Mn0.54-xSnxO2 by powder X-ray diffraction and transmission electron microscopy to be x approximate to 0.045. The limited solubility of Sn is subsequently confirmed by density functional theory calculations. Voltage fade for x= 0 andx= 0.027 has been comparatively assessed within the 3.00 V-4.55 V (vs.Li/Li+) potential window, from which it is concluded that replacing Mn4+ by Sn4+ cannot be considered as a viable strategy to inhibit voltage fade within this window, at least with the given restricted doping level. |
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Wos |
000555330900018 |
Publication Date |
2020-07-09 |
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Abbreviated Series Title |
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Edition |
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ISSN |
0300-9246; 1477-9226; 1472-7773 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
; The authors acknowledge Research Foundation Flanders (FWO) project number G040116N for funding. The authors are grateful to Dr Ken Elen and Greet Cuyvers (imo-imomec, UHasselt and imec) for respectively preliminary PXRD measurements and performing ICP-AES on the monometal precursors. Dr Dmitry Rupasov (Skolkovo Institute of Science and Technology) is acknowledged for performing TGA measurements on the metal sulfate precursors. 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: 4; 2020 IF: 4.029 |
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Call Number |
UA @ admin @ c:irua:171149 |
Serial |
6450 |
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Author |
Jorgensen, M.; Shea, P.T.; Tomich, A.W.; Varley, J.B.; Bercx, M.; Lovera, S.; Cerny, R.; Zhou, W.; Udovic, T.J.; Lavallo, V.; Jensen, T.R.; Wood, B.C.; Stavila, V. |
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Title |
Understanding superionic conductivity in lithium and sodium salts of weakly coordinating closo-hexahalocarbaborate anions |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Chemistry of materials |
Abbreviated Journal |
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Volume |
32 |
Issue |
4 |
Pages |
1475-1487 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Solid-state ion conductors based on closo-polyborate anions combine high ionic conductivity with a rich array of tunable properties. Cation mobility in these systems is intimately related to the strength of the interaction with the neighboring anionic network and the energy for reorganizing the coordination polyhedra. Here, we explore such factors in solid electrolytes with two anions of the weakest coordinating ability, [HCB11H5Cl6](-) and [HCB11H5Br6](-), and a total of 11 polymorphs are identified for their lithium and sodium salts. Our approach combines ab initio molecular dynamics, synchrotron X-ray powder diffraction, differential scanning calorimetry, and AC impedance measurements to investigate their structures, phase-transition behavior, anion orientational mobilities, and ionic conductivities. We find that M(HCB11H5X6) (M = Li, Na, X = Cl, Br) compounds exhibit order-disorder polymorphic transitions between 203 and 305 degrees C and display Li and Na superionic conductivity in the disordered state. Through detailed analysis, we illustrate how cation disordering in these compounds originates from a competitive interplay among the lattice symmetry, the anion reorientational mobility, the geometric and electronic asymmetry of the anion, and the polarizability of the halogen atoms. These factors are compared to other closo-polyborate-based ion conductors to suggest guidelines for optimizing the cation-anion interaction for fast ion mobility. This study expands the known solid-state poly(carba)borate-based materials capable of liquid-like ionic conductivities, unravels the mechanisms responsible for fast ion transport, and provides insights into the development of practical superionic solid electrolytes. |
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Wos |
000517351300014 |
Publication Date |
2020-01-23 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
5 |
Open Access |
OpenAccess |
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Notes |
; The authors gratefully acknowledge support from the Hydrogen Materials-Advanced Research Consortium (HyMARC), established as part of the Energy Materials Network under the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, under Contract no. AC04-94AL85000. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under Contract no. DE-NA-0003525. A portion of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract no. ACS2-07NA27344. We also gratefully thank Kyoung Kweon for useful discussions. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Neither the United States Government nor any agency thereof nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. The Danish council for independent research, technology and production, HyNanoBorN (4181-00462) and SOS-MagBat (9041-00226B) and NordForsk, The Nordic Neutron Science Program, project FunHy (81942), and the Carlsberg Foundation are acknowledged for funding. Affiliation with the Center for Integrated Materials Research (iMAT) at Aarhus University is gratefully acknowledged. V.L. acknowledges the NSF for partial support of this project (DMR-1508537). The authors would like to thank the Swiss-Norwegian beamlines (BM01) at the ESRF, Grenoble, for the help with the data collection, DESY for access to Petra III, at beamline P02.1, and Diamond for access to beamline I11. ; |
Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:167754 |
Serial |
6645 |
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Author |
Choudhary, K.; Bercx, M.; Jiang, J.; Pachter, R.; Lamoen, D.; Tavazza, F. |
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Title |
Accelerated Discovery of Efficient Solar Cell Materials Using Quantum and Machine-Learning Methods |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
31 |
Issue |
15 |
Pages |
5900-5908 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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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. |
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Wos |
000480826900060 |
Publication Date |
2019-08-13 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
6 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 9.466 |
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Call Number |
EMAT @ emat @c:irua:161814 |
Serial |
5291 |
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Author |
Callaert, C.; Bercx, M.; Lamoen, D.; Hadermann, J. |
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Title |
Interstitial defects in the van der Waals gap of Bi2Se3 |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Acta Crystallographica. Section B: Structural Science, Crystal Engineering and Materials (Online) |
Abbreviated Journal |
Acta Crystallogr B |
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Volume |
75 |
Issue |
4 |
Pages |
717-732 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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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. |
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Wos |
000480512600024 |
Publication Date |
2019-08-01 |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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ISSN |
2052-5206 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.032 |
Times cited |
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Open Access |
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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 |
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Call Number |
EMAT @ emat @c:irua:161847 |
Serial |
5295 |
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Author |
Bercx, M.; Slap, L.; Partoens, B.; Lamoen, D. |
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Title |
First-Principles Investigation of the Stability of the Oxygen Framework of Li-Rich Battery Cathodes |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
MRS advances |
Abbreviated Journal |
MRS Adv. |
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Volume |
4 |
Issue |
14 |
Pages |
813-820 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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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. |
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Wos |
000466846700004 |
Publication Date |
2019-02-21 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2059-8521 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
3 |
Open Access |
Not_Open_Access: Available from 22.02.2020
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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 |
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Call Number |
EMAT @ emat @UA @ admin @ c:irua:160121 |
Serial |
5179 |
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Author |
Bercx, M.; Partoens, B.; Lamoen, D. |
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Title |
Quantitative modeling of secondary electron emission from slow-ion bombardment on semiconductors |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
99 |
Issue |
8 |
Pages |
085413 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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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. |
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Wos |
000458367800010 |
Publication Date |
2019-02-11 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
5 |
Open Access |
OpenAccess |
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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 |
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Call Number |
EMAT @ emat @UA @ admin @ c:irua:157174 |
Serial |
5154 |
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Author |
Dimitrievska, M.; Shea, P.; Kweon, K.E.; Bercx, M.; Varley, J.B.; Tang, W.S.; Skripov, A.V.; Stavila, V.; Udovic, T.J.; Wood, B.C. |
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Title |
Carbon Incorporation and Anion Dynamics as Synergistic Drivers for Ultrafast Diffusion in Superionic LiCB11H12 and NaCB11H12 |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Advanced energy materials |
Abbreviated Journal |
Adv Energy Mater |
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Volume |
8 |
Issue |
15 |
Pages |
1703422 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The disordered phases of LiCB11H12 and NaCB11H12 possess superb superionic conductivities that make them suitable as solid electrolytes. In these materials, cation diffusion correlates with high orientational mobilities of the CB11H12- anions; however, the precise relationship has yet to be demonstrated. In this work, ab initio molecular dynamics and quasielastic neutron scattering are combined to probe anion reorientations and their mechanistic connection to cation mobility over a range of timescales and temperatures. It is found that anions do not rotate freely, but rather transition rapidly between orientations defined by the cation sublattice symmetry. The symmetry-breaking carbon atom in CB11H12- also plays a critical role by perturbing the energy landscape along the instantaneous orientation of the anion dipole, which couples fluctuations in the cation probability density directly to the anion motion. Anion reorientation rates exceed 3 x 10(10) s(-1), suggesting the underlying energy landscape fluctuates dynamically on diffusion-relevant timescales. Furthermore, carbon is found to modify the orientational preferences of the anions and aid rotational mobility, creating additional symmetry incompatibilities that inhibit ordering. The results suggest that synergy between the anion reorientational dynamics and the carbon-modified cation-anion interaction accounts for the higher ionic conductivity in CB11H12- salts compared with B12H122-. |
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Publisher |
WILEY-VCH Verlag GmbH & Co. |
Place of Publication |
Weinheim |
Editor |
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Wos |
000434031400026 |
Publication Date |
2018-02-21 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1614-6832; 1614-6840 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
16.721 |
Times cited |
20 |
Open Access |
OpenAccess |
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Notes |
; This work was performed in part under the auspices of the U.S. Department of Energy at Lawrence Livermore National Laboratory (LLNL) under Contract No. DE-AC52-07NA27344 and funded by Laboratory Directed Research and Development Grant 15-ERD-022. Computing support came from the LLNL Institutional Computing Grand Challenge program. This work was also performed in part within the assignment of the Russian Federal Agency of Scientific Organizations (program “Spin” No. 01201463330). The authors gratefully acknowledge support from the Russian Foundation for Basic Research under Grant No. 15-03-01114 and the Ural Branch of the Russian Academy of Sciences under Grant No. 15-9-2-9. A.V.S. gratefully acknowledges travel support from CRDF Global in conjunction with this work under Grant No. FSCX-15-61826-0. M.D. gratefully acknowledges research support from the Hydrogen Materials-Advanced Research Consortium (HyMARC), established as part of the Energy Materials Network under the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, under Contract No. DE-AC36-08GO28308. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy National Nuclear Security Administration under Contract No. DE-AC04-94AL85000. This work utilized facilities supported in part by the National Science Foundation under Agreement No. DMR-1508249. The views, opinions, findings, and conclusions stated herein are those of the authors and do not necessarily reflect those of CRDF Global, or the United States Government or any agency thereof. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. ; |
Approved |
Most recent IF: 16.721 |
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Call Number |
UA @ lucian @ c:irua:152045 |
Serial |
5015 |
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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. |
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Title |
Structure and vacancy distribution in copper telluride nanoparticles influence plasmonic activity in the near-infrared |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Nature communications |
Abbreviated Journal |
Nat Commun |
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Volume |
8 |
Issue |
8 |
Pages |
14925 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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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. |
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Wos |
000397799700001 |
Publication Date |
2017-03-30 |
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ISSN |
2041-1723 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.124 |
Times cited |
37 |
Open Access |
OpenAccess |
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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 |
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Call Number |
EMAT @ emat @ c:irua:142203UA @ admin @ c:irua:142203 |
Serial |
4538 |
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Author |
Bercx, M.; Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D. |
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Title |
First-principles analysis of the spectroscopic limited maximum efficiency of photovoltaic absorber layers for CuAu-like chalcogenides and silicon |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical chemistry, chemical physics |
Abbreviated Journal |
Phys Chem Chem Phys |
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Volume |
18 |
Issue |
18 |
Pages |
20542-20549 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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Abstract |
Chalcopyrite semiconductors are of considerable interest for application as absorber layers in thin-film photovoltaic cells. When growing films of these compounds, however, they are often found to contain CuAu-like domains, a metastable phase of chalcopyrite. It has been reported that for CuInS2, the presence of the CuAu-like phase improves the short circuit current of the chalcopyrite-based photovoltaic cell. We investigate the thermodynamic stability of both phases for a selected list of I-III-VI2 materials using a first-principles density functional theory approach. For the CuIn-VI2 compounds, the difference in formation energy between the chalcopyrite and CuAu-like phase is found to be close to 2 meV per atom, indicating a high likelihood of the presence of CuAu-like domains. Next, we calculate the spectroscopic limited maximum efficiency (SLME) of the CuAu-like phase and compare the results with those of the corresponding chalcopyrite phase. We identify several candidates with a high efficiency, such as CuAu-like CuInS2, for which we obtain an SLME of 29% at a thickness of 500 nm. We observe that the SLME can have values above the Shockley-Queisser (SQ) limit, and show that this can occur because the SQ limit assumes the absorptivity to be a step function, thus overestimating the radiative recombination in the detailed balance approach. This means that it is possible to find higher theoretical efficiencies within this framework simply by calculating the J-V characteristic with an absorption spectrum. Finally, we expand our SLME analysis to indirect band gap absorbers by studying silicon, and find that the SLME quickly overestimates the reverse saturation current of indirect band gap materials, drastically lowering their calculated efficiency. |
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Address |
EMAT & CMT groups, Department of Physics, University of Antwerp, Campus Groenenborger, Groenenborgerlaan 171, 2020 Antwerp, Belgium. marnik.bercx@uantwerpen.be |
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English |
Wos |
000381428600058 |
Publication Date |
2016-07-08 |
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Series Issue |
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Edition |
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ISSN |
1463-9076 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.123 |
Times cited |
34 |
Open Access |
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Notes |
We acknowledge financial support of FWO-Vlaanderen through projects G.0150.13N and G.0216.14N and ERA-NET RUS Plus/FWO, Grant G0D6515N. 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 FWOVlaanderen. |
Approved |
Most recent IF: 4.123 |
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Call Number |
c:irua:135091 |
Serial |
4112 |
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