Records |
Author |
Eijt, S.W.H.; Shi, W.; Mannheim, A.; Butterling, M.; Schut, H.; Egger, W.; Dickmann, M.; Hugenschmidt, C.; Shakeri, B.; Meulenberg, R.W.; Callewaert, V.; Saniz, R.; Partoens, B.; Barbiellini, B.; Bansil, A.; Melskens, J.; Zeman, M.; Smets, A.H.M.; Kulbak, M.; Hodes, G.; Cahen, D.; Brück, E. |
Title |
New insights into the nanostructure of innovative thin film solar cells gained by positron annihilation spectroscopy |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Journal of physics : conference series |
Abbreviated Journal |
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Volume |
791 |
Issue |
791 |
Pages |
012021 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Recent studies showed that positron annihilation methods can provide key insights into the nanostructure and electronic structure of thin film solar cells. In this study, positron annihilation lifetime spectroscopy (PALS) is applied to investigate CdSe quantum dot (QD) light absorbing layers, providing evidence of positron trapping at the surfaces of the QDs. This enables one to monitor their surface composition and electronic structure. Further, 2D-Angular Correlation of Annihilation Radiation (2D-ACAR) is used to investigate the nanostructure of divacancies in photovoltaic-high-quality a-Si:H films. The collected momentum distributions were converted by Fourier transformation to the direct space representation of the electron-positron autocorrelation function. The evolution of the size of the divacancies as a function of hydrogen dilution during deposition of a-Si:H thin films was examined. Finally, we present a first positron Doppler Broadening of Annihilation Radiation (DBAR) study of the emerging class of highly efficient thin film solar cells based on perovskites. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000400610500021 |
Publication Date |
2017-02-22 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue ![sorted by Series Issue field, ascending order (up)](img/sort_asc.gif) |
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Edition |
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ISSN |
1742-6588 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
1 |
Open Access |
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Notes |
The work at Delft University of Technology was supported by the China Scholarship Council (CSC) grant of W.S., by ADEM, A green Deal in Energy Materials of the Ministry of Economic Affairs of The Netherlands (www.adem- innovationlab.nl), and the STW Vidi grant of A.S., Grant No. 10782. The PALS study is based upon experiments performed at the PLEPS instrument of the NEPOMUC facility at the Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany, and was supported by the European Commission under the 7 th Framework Programme, Key Action: Strengthening the European Research Area, Research Infrastructures, Contract No. 226507, NMI3. The work at University of Maine was supported by the National Science Foundation under Grant No. DMR-1206940. Research at the University of Antwerp was supported by FWO grants G022414N and G015013. The work at Northeastern University was supported by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences grant number DE-FG02-07ER46352 (core research), and benefited from Northeastern University's Advanced Scientific Computation Center (ASCC), the NERSC supercomputing center through DOE grant number DE-AC02-05CH11231, and support (applications to layered materials) from the DOE EFRC: Center for the Computational Design of Functional Layered Materials (CCDM) under DE-SC0012575. The work at the Weizmann Institute was supported by the Sidney E. Frank Foundation through the Israel Science Foundation, by the Israel Ministry of Science, and the Israel National Nano-Initiative. D.C. holds the Sylvia and Rowland Schaefer Chair in Energy Research. |
Approved |
Most recent IF: NA |
Call Number |
CMT @ cmt @ c:irua:140850 |
Serial |
4426 |
Permanent link to this record |
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Author |
Shi, W.; Callewaert, V.; Barbiellini, B.; Saniz, R.; Butterling, M.; Egger, W.; Dickmann, M.; Hugenschmidt, C.; Shakeri, B.; Meulenberg, R. W.; Brück, E.; Partoens, B.; Bansil, A.; Eijt, S.W. H. |
Title |
Nature of the Positron State in CdSe Quantum Dots |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
121 |
Issue |
5 |
Pages |
057401 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Previous studies have shown that positron-annihilation spectroscopy is a highly sensitive probe of the electronic structure and surface composition of ligand-capped semiconductor quantum dots (QDs) embedded in thin films. The nature of the associated positron state, however, whether the positron is confined inside the QDs or localized at their surfaces, has so far remained unresolved. Our positron-annihilation lifetime spectroscopy studies of CdSe QDs reveal the presence of a strong lifetime component in the narrow range of 358–371 ps, indicating abundant trapping and annihilation of positrons at the surfaces of the QDs. Furthermore, our ab initio calculations of the positron wave function and lifetime employing a recent formulation of the weighted density approximation demonstrate the presence of a positron surface state and predict positron lifetimes close to experimental values. Our study thus resolves the long-standing question regarding the nature of the positron state in semiconductor QDs and opens the way to extract quantitative information on surface composition and ligand-surface interactions of colloidal semiconductor QDs through highly sensitive positron-annihilation techniques. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000440635300012 |
Publication Date |
2018-08-02 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue ![sorted by Series Issue field, ascending order (up)](img/sort_asc.gif) |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
6 |
Open Access |
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Notes |
The work at Delft University of Technology was supported by the China Scholarship Council (CSC) grant of W. S. We acknowledge financial support for this research from ADEM, A green Deal in Energy Materials of the Ministry of Economic Affairs of The Netherlands. The PALS study is based upon experiments performed at the PLEPS instrument of the NEPOMUC facility at the Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany, and was supported by the European Commission under the 7th Framework Program, Key Action: Strengthening the European Research Area, Research Infrastructures, Contract No. 226507, NMI3. The work at the University of Maine was supported by the National Science Foundation under Grant No. DMR-1206940. V. C. and R. S. were supported by the FWO-Vlaanderen through Project No. G. 0224.14N. Computational resources and services used in this work were in part 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 (EWI Department). The work at Northeastern University was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences Grant No. DE-FG02-07ER46352 (core research), and benefited from Northeastern University’s Advanced Scientific Computation Center (ASCC), the National Energy Research Scientific Computing Center (NERSC) through DOE Grant No. DE-AC02-05CH11231, and support (functionals for modeling positron spectros- copies of layered materials) from the DOE EFRC: Center for the Computational Design of Functional Layered Materials (CCDM) under DE-SC0012575. |
Approved |
Most recent IF: 8.462 |
Call Number |
CMT @ cmt @c:irua:152999UA @ admin @ c:irua:152999 |
Serial |
5009 |
Permanent link to this record |
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Author |
Van Goethem, C.; Verbeke, R.; Pfanmoeller, M.; Koschine, T.; Dickmann, M.; Timpel-Lindner, T.; Egger, W.; Bals, S.; Vankelecom, I.F.J. |
Title |
The role of MOFs in Thin-Film Nanocomposite (TFN) membranes |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Journal of membrane science |
Abbreviated Journal |
J Membrane Sci |
Volume |
563 |
Issue |
563 |
Pages |
938-948 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Incorporation of MOFs in interfacially polymerized Thin-Film Nanocomposite (TFN) membranes has widely been shown to result in increased membrane performance. However, the exact functioning of these membranes is poorly understood as large variability in permeance increase, filler incorporation and rejection changes can be observed in literature. The synthesis and functioning of TFN membranes (herein exemplified by ZIF-8 filled polyamide (PA) membranes prepared via the EFP method) was investigated via targeted membrane synthesis and thorough characterization via STEM-EDX, XRD and PALS. It is hypothesized that the acid generated during the interfacial polymerization (IP) at least partially degrades the crystalline, acid-sensitive ZIF-8 and that this influences the membrane formation (through so-called secondary effects, i.e. not strictly linked to the pore morphology of the MOF). Nanoscale HAADF-STEM imaging and STEM-EDX Zn-mapping revealed no ZIF-8 particles but rather the presence of randomly shaped regions with elevated Zn-content. Also XRD failed to show the presence of crystalline areas in the composite PA films. As the addition of the acid-quenching TEA led to an increase in the diffraction signal observed in XRD, the role of the acid was confirmed. The separate addition of dissolved Zn2+ to the synthesis of regular TFC membranes showed an increase in permeance while losing some salt retention, similar to observations regularly made for TFN membranes. While the addition of a porous material to a TFC membrane is a straightforward concept, all obtained results indicate that the synthesis and performance of such composite membranes is often more complex than commonly accepted. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000441897200099 |
Publication Date |
2018-06-22 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue ![sorted by Series Issue field, ascending order (up)](img/sort_asc.gif) |
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Edition |
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ISSN |
0376-7388 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.035 |
Times cited |
84 |
Open Access |
OpenAccess |
Notes |
; C.V.G. and R.V. kindly acknowledge respectively the Flemish Agency for Innovation through Science and Technology (IWT) (IWT, 141697) and the Flemish Fund for Scientific Research (FWO, 1500917N) for a PhD scholarship. The authors kindly acknowledge funding from KU Leuven through C16/17/005 and from the Belgian Federal Government through IAP 6/27 Functional Supramolecular systems. S.B. and M.P. acknowledge financial support from the European Research Council (ERC Starting Grant #335078-COLOURATOM). M.P. acknowledges funding from the European Union (ESTEEM2, No. 312483) and the HEiKA centre FunTECH-3D (Ministry of Science, Research and Art Baden-Wurttemberg, AZ: 33-753-30-20/3/3). The MLZ-Garching is kindly acknowledged for providing access to the NEPOMUC facilities (project no 11541). ; ecas_sara |
Approved |
Most recent IF: 6.035 |
Call Number |
UA @ lucian @ c:irua:153618UA @ admin @ c:irua:153618 |
Serial |
5132 |
Permanent link to this record |