1
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Pyatenko E, Hauschild D, Mikhnych V, Edla R, Steininger R, Hariskos D, Witte W, Powalla M, Heske C, Weinhardt L. Rb Diffusion and Oxide Removal at the RbF-Treated Ga 2O 3/Cu(In,Ga)Se 2 Interface in Thin-Film Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2023; 15. [PMID: 37913778 PMCID: PMC10659031 DOI: 10.1021/acsami.3c11165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 10/07/2023] [Accepted: 10/10/2023] [Indexed: 11/03/2023]
Abstract
We report on the chemical structure of Cu(In,Ga)Se2 (CIGSe) thin-film solar cell absorber surfaces and their interface with a sputter-deposited Ga2O3 buffer. The CIGSe samples were exposed to a RbF postdeposition treatment and an ammonia-based rinsing step, as used in corresponding thin-film solar cells. For a detailed chemical analysis of the impact of these treatments, we employed laboratory-based X-ray photoelectron spectroscopy, X-ray-excited Auger electron spectroscopy, and synchrotron-based hard X-ray photoelectron spectroscopy. On the RbF-treated surface, we find both Rb and F, which are then partly (Rb) and completely (F) removed by the rinse. The rinse also removes Ga-F, Ga-O, and In-O surface bonds and reduces the Ga/(Ga + In) ratio at the CIGSe absorber surface. After Ga2O3 deposition, we identify the formation of In oxides and the diffusion of Rb and small amounts of F into/onto the Ga2O3 buffer layer but no indication of the formation of hydroxides.
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Affiliation(s)
- Elizaveta Pyatenko
- Laboratory
for Applications of Synchrotron Radiation (LAS), Karlsruhe Institute of Technology (KIT), Kaiserstraße 12, Karlsruhe 76131, Germany
- Institute
for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, Eggenstein-Leopoldshafen 76344, Germany
| | - Dirk Hauschild
- Institute
for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, Eggenstein-Leopoldshafen 76344, Germany
- Institute
for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Engesserstraße 18/20, Karlsruhe 76128, Germany
- Department
of Chemistry and Biochemistry, University
of Nevada, Las Vegas (UNLV), 4505 Maryland Parkway, Las Vegas, Nevada 89154-4003, United States
| | - Vladyslav Mikhnych
- Institute
for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, Eggenstein-Leopoldshafen 76344, Germany
| | - Raju Edla
- Institute
for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, Eggenstein-Leopoldshafen 76344, Germany
| | - Ralph Steininger
- Institute
for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, Eggenstein-Leopoldshafen 76344, Germany
| | - Dimitrios Hariskos
- Zentrum
für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg
(ZSW), Meitnerstraße
1, Stuttgart 70563, Germany
| | - Wolfram Witte
- Zentrum
für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg
(ZSW), Meitnerstraße
1, Stuttgart 70563, Germany
| | - Michael Powalla
- Zentrum
für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg
(ZSW), Meitnerstraße
1, Stuttgart 70563, Germany
| | - Clemens Heske
- Institute
for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, Eggenstein-Leopoldshafen 76344, Germany
- Institute
for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Engesserstraße 18/20, Karlsruhe 76128, Germany
- Department
of Chemistry and Biochemistry, University
of Nevada, Las Vegas (UNLV), 4505 Maryland Parkway, Las Vegas, Nevada 89154-4003, United States
| | - Lothar Weinhardt
- Institute
for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, Eggenstein-Leopoldshafen 76344, Germany
- Institute
for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Engesserstraße 18/20, Karlsruhe 76128, Germany
- Department
of Chemistry and Biochemistry, University
of Nevada, Las Vegas (UNLV), 4505 Maryland Parkway, Las Vegas, Nevada 89154-4003, United States
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Kim K, Jung C, Yim K, Jeong I, Shin D, Hwang I, Song S, Ahn SK, Eo YJ, Cho A, Cho JS, Park JH, Choi PP, Yun JH, Gwak J. Atom-Scale Chemistry in Chalcopyrite-Based Photovoltaic Materials Visualized by Atom Probe Tomography. ACS APPLIED MATERIALS & INTERFACES 2022; 14:52825-52837. [PMID: 36346616 DOI: 10.1021/acsami.2c14321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Chalcopyrite-based materials for photovoltaic devices tend to exhibit complex structural imperfections originating from their polycrystalline nature; nevertheless, properly controlled devices are surprisingly irrelevant to them in terms of resulting device performances. The present work uses atom probe tomography to characterize co-evaporated high-quality Cu(In,Ga)Se2 (CIGS) films on flexible polyimide substrates either with or without doping with Na or doping with Na followed by K via a post-deposition treatment. The intent is to elucidate the unique characteristics of the grain boundaries (GBs) in CIGS, in particular the correlations/anti-correlations between matrix elements and the alkali dopants. Various compositional fluctuations are identified at GBs irrespective of the presence of alkali elements. However, [Cu-poor and Se/In,Ga-rich] GBs are significantly more common than [Cu-rich and Se/In,Ga-poor] ones. In addition, the anti-correlations between Cu and the other matrix elements are found to show not only regular trends among themselves but also the association with the degree of alkali segregation at GBs. The Na and K concentrations exhibited a correlation at the GBs but not in the intragrain regions. Density functional theory calculations are used to explain the compositional fluctuations and alkali segregation at the GBs. Our experimental and theoretical findings not only reveal the benign or beneficial characteristics of the GBs of CIGS but also provide a fundamental understanding of the GB chemistry in CIGS-based materials.
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Affiliation(s)
- Kihwan Kim
- Photovoltaics Research Department, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
- University of Science and Technology, Daejeon34113, Republic of Korea
| | - Chanwon Jung
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon34141, Republic of Korea
| | - Kanghoon Yim
- Computational Science and Engineering Laboratory, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
| | - Inyoung Jeong
- Photovoltaics Research Department, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
| | - Donghyeop Shin
- Photovoltaics Research Department, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
| | - Inchan Hwang
- Photovoltaics Research Department, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
| | - Soomin Song
- Photovoltaics Research Department, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
| | - Seung Kyu Ahn
- Photovoltaics Research Department, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
| | - Young-Joo Eo
- Photovoltaics Research Department, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
| | - Ara Cho
- Photovoltaics Research Department, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
| | - Jun-Sik Cho
- Photovoltaics Research Department, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
| | - Joo Hyung Park
- Photovoltaics Research Department, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
| | - Pyuck-Pa Choi
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon34141, Republic of Korea
| | - Jae Ho Yun
- Institute for Energy Materials and Devices, Korea Institute of Energy Technology, Naju-si, Jeollanam-do58339, Republic of Korea
| | - Jihye Gwak
- University of Science and Technology, Daejeon34113, Republic of Korea
- New and Renewable Energy Institute, Korea Institute of Energy Research, Daejeon34129, Republic of Korea
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Nagai T, Nishinaga J, Tampo H, Kim S, Hirayama K, Matsunobe T, Chen G, Ide Y, Ishizuka S, Shibata H, Niki S, Terada N. Impacts of KF Post-Deposition Treatment on the Band Alignment of Epitaxial Cu(In,Ga)Se 2 Heterojunctions. ACS APPLIED MATERIALS & INTERFACES 2022; 14:16780-16790. [PMID: 35380044 DOI: 10.1021/acsami.1c21193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In this study, we investigated band alignments at CdS/epitaxial CuInxGa1-xSe2 (epi-CIGSe) and epi-CIGSe/GaAs heterointerfaces for solar cell applications using ultraviolet, inverse, and X-ray photoemission spectroscopy (UPS, IPES, and XPS) techniques. We clarified the impacts of KF postdeposition treatment (KF-PDT) at the CdS/epi-CIGSe front heterointerfaces. We found that KF-PDT changed the conduction band alignment at the CdS/epi-CIGSe heterointerface from a cliff to flat configuration, attributed to an increase in the electron affinity (EA) and ionization potential (IP) of the epi-CIGSe surface because of a decrease in Cu and Ga contents. Herein, we discuss the correlation between the impacts of KF-PDT and the solar cell performance. Furthermore, we also investigated the band alignment at the epi-CIGSe/GaAs rear heterointerface. Electron barriers were formed at the epi-CIGSe/GaAs interface, suppressing carrier recombination as the back surface field. Contrarily, a hole accumulation layer is formed by the valence band bending, which is like Ohmic contact.
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Affiliation(s)
- Takehiko Nagai
- Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Jiro Nishinaga
- Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Hitoshi Tampo
- Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Shinho Kim
- Institute of Materials Technology, Pusan National University, Busan 46241, Republic of Korea
| | - Kazuhiro Hirayama
- Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan
| | - Tatsuo Matsunobe
- Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan
| | - Guanzhong Chen
- Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan
| | - Yuya Ide
- Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan
| | - Shogo Ishizuka
- Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Hajime Shibata
- Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Shigeru Niki
- Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Norio Terada
- Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan
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4
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Martin NM, Törndahl T, Wallin E, Simonov KA, Rensmo H, Platzer-Björkman C. Surface/Interface Effects by Alkali Postdeposition Treatments of (Ag,Cu)(In,Ga)Se 2 Thin Film Solar Cells. ACS APPLIED ENERGY MATERIALS 2022; 5:461-468. [PMID: 35098042 PMCID: PMC8790805 DOI: 10.1021/acsaem.1c02990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
Ag alloying and the introduction of alkali elements through a postdeposition treatment are two approaches to improve the performance of Cu(In,Ga)Se2 (CIGS) thin film solar cells. In particular, a postdeposition treatment of an alkali metal fluoride of the absorber has shown a beneficial effect on the solar cells performance due to an increase in the open circuit voltage (V OC) for both (Ag,Cu)(In,Ga)Se2 (ACIGS) and CIGS based solar cells. Several reasons have been suggested for the improved V OC in CIGS solar cells including absorber surface and interface effects. Less works investigated how the applied postdeposition treatment influences the ACIGS absorber surface and interface properties and the subsequent buffer layer growth. In this work we employed hard X-ray photoelectron spectroscopy to study the chemical and electronic properties at the real functional interface between a CdS buffer and ACIGS absorbers that have been exposed to different alkali metal fluoride treatments during preparation. All samples show an enhanced Ag content at the CdS/ACIGS interface as compared to ACIGS bulk-like composition, and it is also shown that this enhanced Ag content anticorrelates with Ga content. The results indicate that the absorber composition at the near-surface region changes depending on the applied alkali postdeposition treatment. The Cu and Ga decrease and the Ag increase are stronger for the RbF treatment as compared to the CsF treatment, which correlates with the observed device characteristics. This suggests that a selective alkali postdeposition treatment could change the ACIGS absorber surface composition, which can influence the solar cell behavior.
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Affiliation(s)
- Natalia M. Martin
- Solar
Cell Technology, Department of Materials Science and Engineering, Uppsala University, Uppsala, 751 21, Sweden
| | - Tobias Törndahl
- Solar
Cell Technology, Department of Materials Science and Engineering, Uppsala University, Uppsala, 751 21, Sweden
| | - Erik Wallin
- Solibro
Research AB, Vallvägen 5, Uppsala, 756 51, Sweden
| | - Konstantin A. Simonov
- Molecular
and Condensed Matter, Department of Physics and Astronomy, Uppsala University, Uppsala, 751 21, Sweden
| | - Håkan Rensmo
- Molecular
and Condensed Matter, Department of Physics and Astronomy, Uppsala University, Uppsala, 751 21, Sweden
| | - Charlotte Platzer-Björkman
- Solar
Cell Technology, Department of Materials Science and Engineering, Uppsala University, Uppsala, 751 21, Sweden
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5
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Lee WJ, Cho DH, Wi JH, Yu JH, Kim WJ, Kang C, Kang SJ, Chung YD. Evolution of Morphological and Chemical Properties at p-n Junction of Cu(In,Ga)Se 2 Solar Cells with Zn(O,S) Buffer Layer as a Function of KF Postdeposition Treatment Time. ACS APPLIED MATERIALS & INTERFACES 2021; 13:48611-48621. [PMID: 34636529 DOI: 10.1021/acsami.1c12636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We carried out KF postdeposition treatment (PDT) on a Cu(In,Ga)Se2 (CIGS) layer with a process time varying from 50 to 200 s. The highest CIGS solar-cell efficiency was achieved at a KF PDT process time of 50 s; in this condition, we observed the highest level of K element at the near-surface of the CIGS layer and the perfectly passivated pinholes on the CIGS surface. At process times above 150 s, the oversupplied KF agglomerated into large islands and was subsequently eliminated during the deposition of the chemical bath deposition (CBD)-Zn(O,S) buffer layer owing to the islands' water-soluble characteristics. As a result, the growth mechanism of the CBD-Zn(O,S) layer varied as a function of KF PDT process time. X-ray photoemission spectroscopy (XPS) measurements were used to examine the dependency of the chemical state on the KF PDT process time, and from the results, we formulated a chemical reaction model based on the shift in the elemental binding energy following deposition of the CBD-Zn(O,S) buffer layer. The chemical states of the K-In-Se phase, which have a beneficial effect on the solar-cell performance owing to the formation of durable and improved p-n junctions, are formed only at a KF PDT process time of 50 s. We derived band alignments from the XPS depth profiles by extracting the conduction- and valence-band offsets, and we used optical-pump-THz-probe spectroscopy to measure the ultrafast photocarrier lifetimes related to the defect states following KF PDT. Our key findings can be summarized as follows: (i) photocarrier transport is beneficial at a low barrier height, and (ii) the photocarrier lifetime increases when the K-In-Se phases are formed on the CIGS surface, which allows K+ ions to be effectively substituted into Cu vacancies.
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Affiliation(s)
- Woo-Jung Lee
- ICT Creative Research Laboratory, Electronics and Telecommunications Research Institute, Daejeon 34129, Korea
- Department of Advanced Device Technology, Korea University of Science and Technology, Daejeon 34113, Korea
| | - Dae-Hyung Cho
- ICT Creative Research Laboratory, Electronics and Telecommunications Research Institute, Daejeon 34129, Korea
- Department of Advanced Device Technology, Korea University of Science and Technology, Daejeon 34113, Korea
| | - Jae-Hyung Wi
- School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 06974, Korea
| | - Jong Hun Yu
- ICT Creative Research Laboratory, Electronics and Telecommunications Research Institute, Daejeon 34129, Korea
- Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Gyeonggi-do 17104, Korea
| | - Woo-Ju Kim
- ICT Creative Research Laboratory, Electronics and Telecommunications Research Institute, Daejeon 34129, Korea
- Department of Advanced Device Technology, Korea University of Science and Technology, Daejeon 34113, Korea
| | - Chul Kang
- Advanced Photonics Research Institute, Gwangju Institute Science Technology, Gwangju 61005, Korea
| | - Seong Jun Kang
- Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Gyeonggi-do 17104, Korea
| | - Yong-Duck Chung
- ICT Creative Research Laboratory, Electronics and Telecommunications Research Institute, Daejeon 34129, Korea
- Department of Advanced Device Technology, Korea University of Science and Technology, Daejeon 34113, Korea
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Lopes TS, de Wild J, Rocha C, Violas A, Cunha JMV, Teixeira JP, Curado MA, Oliveira AJN, Borme J, Birant G, Brammertz G, Fernandes PA, Vermang B, Salomé PMP. On the Importance of Joint Mitigation Strategies for Front, Bulk, and Rear Recombination in Ultrathin Cu(In,Ga)Se 2 Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2021; 13:27713-27725. [PMID: 34086435 DOI: 10.1021/acsami.1c07943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Several optoelectronic issues, such as poor optical absorption and recombination, limit the power conversion efficiency of ultrathin Cu(In,Ga)Se2 (CIGS) solar cells. To mitigate recombination losses, two combined strategies were implemented: a potassium fluoride (KF) post-deposition treatment (PDT) and a rear interface passivation strategy based on an aluminum oxide (Al2O3) point contact structure. The simultaneous implementation of both strategies is reported for the first time on ultrathin CIGS devices. Electrical measurements and 1D simulations demonstrate that in specific conditions, devices with only KF-PDT may outperform rear interface passivation based devices. By combining KF-PDT and rear interface passivation, an enhancement in an open-circuit voltage of 178 mV is reached over devices that have a rear passivation only, and of 85 mV over devices with only a KF-PDT process. Time-Resolved Photoluminescence measurements showed the beneficial effects of combining KF-PDT and the rear interface passivation at decreasing recombination losses in the studied devices, enhancing charge carrier lifetime. X-ray photoelectron spectroscopy measurements indicate the presence of an In and Se-rich layer that we linked to be a KInSe2 layer. Our results suggest that when bulk and front interface recombination values are very high, they dominate, and individual passivation strategies work poorly. Hence, this work shows that for ultrathin devices, passivation mitigation strategies need to be implemented in tandem.
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Affiliation(s)
- Tomás S Lopes
- INL - International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, 4715-330 Braga, Portugal
- Imec division IMOMEC (partner in Solliance), Wetenschapspark 1, 3590 Diepenbeek, Belgium
- Institute for Material Research (IMO), Hasselt University (partner in Solliance), Agoralaangebouw H, Diepenbeek 3590, Belgium
- EnergyVille, Thorpark, Poort Genk 8310 & 8320, 3600 Genk, Belgium
| | - Jessica de Wild
- Imec division IMOMEC (partner in Solliance), Wetenschapspark 1, 3590 Diepenbeek, Belgium
- Institute for Material Research (IMO), Hasselt University (partner in Solliance), Agoralaangebouw H, Diepenbeek 3590, Belgium
- EnergyVille, Thorpark, Poort Genk 8310 & 8320, 3600 Genk, Belgium
| | - Célia Rocha
- INL - International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, 4715-330 Braga, Portugal
| | - André Violas
- INL - International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, 4715-330 Braga, Portugal
| | - José M V Cunha
- INL - International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, 4715-330 Braga, Portugal
- i3N, Departamento de Física da Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
- Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Jennifer P Teixeira
- INL - International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, 4715-330 Braga, Portugal
| | - Marco A Curado
- INL - International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, 4715-330 Braga, Portugal
- Department of Physics, University of Coimbra, CFisUC, R. Larga, P-3004-516 Coimbra, Portugal
| | - António J N Oliveira
- INL - International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, 4715-330 Braga, Portugal
| | - Jérôme Borme
- INL - International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, 4715-330 Braga, Portugal
| | - Gizem Birant
- Imec division IMOMEC (partner in Solliance), Wetenschapspark 1, 3590 Diepenbeek, Belgium
- Institute for Material Research (IMO), Hasselt University (partner in Solliance), Agoralaangebouw H, Diepenbeek 3590, Belgium
- EnergyVille, Thorpark, Poort Genk 8310 & 8320, 3600 Genk, Belgium
| | - Guy Brammertz
- Imec division IMOMEC (partner in Solliance), Wetenschapspark 1, 3590 Diepenbeek, Belgium
- Institute for Material Research (IMO), Hasselt University (partner in Solliance), Agoralaangebouw H, Diepenbeek 3590, Belgium
- EnergyVille, Thorpark, Poort Genk 8310 & 8320, 3600 Genk, Belgium
| | - Paulo A Fernandes
- INL - International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, 4715-330 Braga, Portugal
- CIETI, Departamento de Física, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Porto 4200-072, Portugal
| | - Bart Vermang
- Imec division IMOMEC (partner in Solliance), Wetenschapspark 1, 3590 Diepenbeek, Belgium
- Institute for Material Research (IMO), Hasselt University (partner in Solliance), Agoralaangebouw H, Diepenbeek 3590, Belgium
- EnergyVille, Thorpark, Poort Genk 8310 & 8320, 3600 Genk, Belgium
| | - Pedro M P Salomé
- INL - International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, 4715-330 Braga, Portugal
- Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
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7
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Gao Q, Zhang Y, Ao J, Bi J, Yao L, Guo J, Sun G, Liu W, Liu F, Zhang Y, Li W. New Solution-Processed Surface Treatment to Improve the Photovoltaic Properties of Electrodeposited Cu(In,Ga)Se 2 (CIGSe) Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2021; 13:25451-25460. [PMID: 34009933 DOI: 10.1021/acsami.1c00270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The surface Ga content for a CIGSe absorber was closely related to variation in the open-circuit voltage (VOC), while it was generally low on a CIGSe surface fabricated by two-step selenization. In this work, a solution-processed surface treatment based on spin-coating GaCl3 solution onto a CIGSe surface was applied to increase the Ga content on the surface. XPS, XRD, Raman spectroscopy, and band gap extraction based on the external quantum efficiency response demonstrated that GaCl3 post deposition treatment (GaCl3-PDT) can be used to enhance the Ga content on the surface of a CIGSe absorber. Meanwhile, a solution-processed surface treatment with KSCN (KSCN-PDT) was employed to form a transmission barrier for holes by moving the valence band maximum downward and decreasing the interface recombination between the CdS and CIGSe layers. Admittance spectroscopy results revealed that deep defects were passivated by GaCl3-PDT or KSCN-PDT. By applying the combination of GaCl3-PDT and KSCN-PDT, a champion device was realized that exhibited an efficiency of 13.5% with an improved VOC of 610 mV. Comparing the efficiency of the untreated CIGSe solar cells (11.7%), the CIGSe device efficiency with GaCl3-PDT and KSCN-PDT exhibited 15% enhancement.
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Affiliation(s)
- Qing Gao
- Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Engineering Research Center of Thin Film Photo-electronic Technology, Ministry of Education, Institute of Photo-electronic Thin Film Devices and Technology of Nankai University, Tianjin 300350, P.R. China
| | - Yongheng Zhang
- Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Engineering Research Center of Thin Film Photo-electronic Technology, Ministry of Education, Institute of Photo-electronic Thin Film Devices and Technology of Nankai University, Tianjin 300350, P.R. China
| | - Jianping Ao
- Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Engineering Research Center of Thin Film Photo-electronic Technology, Ministry of Education, Institute of Photo-electronic Thin Film Devices and Technology of Nankai University, Tianjin 300350, P.R. China
| | - Jinlian Bi
- Tianjin Key Laboratory of Film Electronic and Communication Devices School of Electrical and Electronic Engineering, Tianjin University of Technology, Tianjin 300384, China
| | - Liyong Yao
- Tianjin Institute of Power Source, Tianjin 300384, P. R. China
| | - Jiajia Guo
- Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Engineering Research Center of Thin Film Photo-electronic Technology, Ministry of Education, Institute of Photo-electronic Thin Film Devices and Technology of Nankai University, Tianjin 300350, P.R. China
| | - Guozhong Sun
- Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Engineering Research Center of Thin Film Photo-electronic Technology, Ministry of Education, Institute of Photo-electronic Thin Film Devices and Technology of Nankai University, Tianjin 300350, P.R. China
| | - Wei Liu
- Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Engineering Research Center of Thin Film Photo-electronic Technology, Ministry of Education, Institute of Photo-electronic Thin Film Devices and Technology of Nankai University, Tianjin 300350, P.R. China
| | - Fangfang Liu
- Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Engineering Research Center of Thin Film Photo-electronic Technology, Ministry of Education, Institute of Photo-electronic Thin Film Devices and Technology of Nankai University, Tianjin 300350, P.R. China
| | - Yi Zhang
- Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Engineering Research Center of Thin Film Photo-electronic Technology, Ministry of Education, Institute of Photo-electronic Thin Film Devices and Technology of Nankai University, Tianjin 300350, P.R. China
| | - Wei Li
- Tianjin Key Laboratory of Film Electronic and Communication Devices School of Electrical and Electronic Engineering, Tianjin University of Technology, Tianjin 300384, China
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8
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Rusu M, Kodalle T, Choubrac L, Barreau N, Kaufmann CA, Schlatmann R, Unold T. Electronic Structure of the CdS/Cu(In,Ga)Se 2 Interface of KF- and RbF-Treated Samples by Kelvin Probe and Photoelectron Yield Spectroscopy. ACS APPLIED MATERIALS & INTERFACES 2021; 13:7745-7755. [PMID: 33529003 DOI: 10.1021/acsami.0c20976] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ambient-pressure Kelvin probe and photoelectron yield spectroscopy methods were employed to investigate the impact of the KF and RbF postdeposition treatments (KF-PDT, RbF-PDT) on the electronic features of Cu(In,Ga)Se2 (CIGSe) thin films and the CdS/CIGSe interface in a CdS thickness series that has been sequentially prepared during the chemical bath deposition (CBD) process depending on the deposition time. We observe distinct features correlated to the CBD-CdS growth stages. In particular, we find that after an initial CBD etching stage, the valence band maximum (VBM) of the CIGSe surface is significantly shifted (by 180-620 mV) toward the Fermi level. However, VBM positions at the surface of the CIGSe are still much below the VBM of the CIGSe bulk. The CIGSe surface band gap is found to depend on the type of postdeposition treatment, showing values between 1.46 and 1.58 eV, characteristic for a copper-poor CIGSe surface composition. At the CdS/CIGSe interface, the lowest VBM discontinuity is observed for the RbF-PDT sample. At this interface, a thin layer with a graded band gap is found. We also find that K and Rb act as compensating acceptors in the CdS layer. Detailed energy band diagrams of the CdS/CIGSe heterostructures are proposed.
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Affiliation(s)
- Marin Rusu
- Struktur und Dynamik von Energiematerialien, Helmholtz-Zentrum Berlin für Materialien und Energie, Lise-Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Tim Kodalle
- PVcomB, Helmholtz-Zentrum Berlin für Materialien und Energie, Schwarzschildstr. 3, 12489 Berlin, Germany
| | - Leo Choubrac
- Struktur und Dynamik von Energiematerialien, Helmholtz-Zentrum Berlin für Materialien und Energie, Lise-Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Nicolas Barreau
- Université de Nantes, CNRS, Institut des Matériaux Jean Rouxel, IMN, F-44000 Nantes, France
| | - Christian A Kaufmann
- PVcomB, Helmholtz-Zentrum Berlin für Materialien und Energie, Schwarzschildstr. 3, 12489 Berlin, Germany
| | - Rutger Schlatmann
- PVcomB, Helmholtz-Zentrum Berlin für Materialien und Energie, Schwarzschildstr. 3, 12489 Berlin, Germany
| | - Thomas Unold
- Struktur und Dynamik von Energiematerialien, Helmholtz-Zentrum Berlin für Materialien und Energie, Lise-Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
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9
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Aboulfadl H, Sopiha KV, Keller J, Larsen JK, Scragg JJ, Persson C, Thuvander M, Edoff M. Alkali Dispersion in (Ag,Cu)(In,Ga)Se 2 Thin Film Solar Cells-Insight from Theory and Experiment. ACS APPLIED MATERIALS & INTERFACES 2021; 13:7188-7199. [PMID: 33534535 PMCID: PMC7898268 DOI: 10.1021/acsami.0c20539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/25/2021] [Indexed: 06/12/2023]
Abstract
Silver alloying of Cu(In,Ga)Se2 absorbers for thin film photovoltaics offers improvements in open-circuit voltage, especially when combined with optimal alkali-treatments and certain Ga concentrations. The relationship between alkali distribution in the absorber and Ag alloying is investigated here, combining experimental and theoretical studies. Atom probe tomography analysis is implemented to quantify the local composition in grain interiors and at grain boundaries. The Na concentration in the bulk increases up to ∼60 ppm for [Ag]/([Ag] + [Cu]) = 0.2 compared to ∼20 ppm for films without Ag and up to ∼200 ppm for [Ag]/([Ag] + [Cu]) = 1.0. First-principles calculations were employed to evaluate the formation energies of alkali-on-group-I defects (where group-I refers to Ag and Cu) in (Ag,Cu)(In,Ga)Se2 as a function of the Ag and Ga contents. The computational results demonstrate strong agreement with the nanoscale analysis results, revealing a clear trend of increased alkali bulk solubility with the Ag concentration. The present study, therefore, provides a more nuanced understanding of the role of Ag in the enhanced performance of the respective photovoltaic devices.
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Affiliation(s)
- Hisham Aboulfadl
- Division
of Microstructure Physics, Department of Physics, Chalmers University of Technology, 41296 Göteborg, Sweden
| | - Kostiantyn V. Sopiha
- Division
of Solar Cell Technology, Department of Materials Science and Engineering, Uppsala University, 75121 Uppsala, Sweden
| | - Jan Keller
- Division
of Solar Cell Technology, Department of Materials Science and Engineering, Uppsala University, 75121 Uppsala, Sweden
| | - Jes K. Larsen
- Division
of Solar Cell Technology, Department of Materials Science and Engineering, Uppsala University, 75121 Uppsala, Sweden
| | - Jonathan J.S. Scragg
- Division
of Solar Cell Technology, Department of Materials Science and Engineering, Uppsala University, 75121 Uppsala, Sweden
| | - Clas Persson
- Center
of Materials Science and Nanotechnology, Department of Physics, University of Oslo, 0316 Oslo, Norway
- Division
of Applied Materials Physics, Department of Materials Science and
Engineering, KTH Royal Institute of Technology, 10044 Stockholm, Sweden
| | - Mattias Thuvander
- Division
of Microstructure Physics, Department of Physics, Chalmers University of Technology, 41296 Göteborg, Sweden
| | - Marika Edoff
- Division
of Solar Cell Technology, Department of Materials Science and Engineering, Uppsala University, 75121 Uppsala, Sweden
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10
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Mirhosseini H, Kormath Madam Raghupathy R, Sahoo SK, Wiebeler H, Chugh M, Kühne TD. In silico investigation of Cu(In,Ga)Se 2-based solar cells. Phys Chem Chem Phys 2020; 22:26682-26701. [PMID: 33236749 DOI: 10.1039/d0cp04712k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Photovoltaics is one of the most promising and fastest-growing renewable energy technologies. Although the price-performance ratio of solar cells has improved significantly over recent years, further systematic investigations are needed to achieve higher performance and lower cost for future solar cells. In conjunction with experiments, computer simulations are powerful tools to investigate the thermodynamics and kinetics of solar cells. Over the last few years, we have developed and employed advanced computational techniques to gain a better understanding of solar cells based on copper indium gallium selenide (Cu(In,Ga)Se2). Furthermore, we have utilized state-of-the-art data-driven science and machine learning for the development of photovoltaic materials. In this Perspective, we review our results along with a survey of the field.
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Affiliation(s)
- Hossein Mirhosseini
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Warburger Str. 100, 33098 Paderborn, Germany.
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11
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Kim JH, Kim MK, Gadisa A, Stuard SJ, Nahid MM, Kwon S, Bae S, Kim B, Park GS, Won DH, Lee DK, Kim DW, Shin TJ, Do YR, Kim J, Choi WJ, Ade H, Min BK. Morphological-Electrical Property Relation in Cu(In,Ga)(S,Se) 2 Solar Cells: Significance of Crystal Grain Growth and Band Grading by Potassium Treatment. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2003865. [PMID: 33150725 DOI: 10.1002/smll.202003865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/27/2020] [Indexed: 06/11/2023]
Abstract
Solution-processed Cu(In,Ga)(S,Se)2 (CIGS) has a great potential for the production of large-area photovoltaic devices at low cost. However, CIGS solar cells processed from solution exhibit relatively lower performance compared to vacuum-processed devices because of a lack of proper composition distribution, which is mainly instigated by the limited Se uptake during chalcogenization. In this work, a unique potassium treatment method is utilized to improve the selenium uptake judiciously, enhancing grain sizes and forming a wider bandgap minimum region. Careful engineering of the bandgap grading structure also results in an enlarged space charge region, which is favorable for electron-hole separation and efficient charge carrier collection. Besides, this device processing approach has led to a linearly increasing electron diffusion length and carrier lifetime with increasing the grain size of the CIGS film, which is a critical achievement for enhancing photocurrent yield. Overall, 15% of power conversion efficiency is achieved in solar cells processed from environmentally benign solutions. This approach offers critical insights for precise device design and processing rules for solution-processed CIGS solar cells.
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Affiliation(s)
- Joo-Hyun Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Min Kyu Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Abay Gadisa
- Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, 851 Main Campus Dr., Raleigh, NC, 27695, USA
| | - Samuel J Stuard
- Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, 851 Main Campus Dr., Raleigh, NC, 27695, USA
| | - Masrur Morshed Nahid
- Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, 851 Main Campus Dr., Raleigh, NC, 27695, USA
| | - Soyeong Kwon
- Department of Physics, Ewha Womans University, 52, Ewhayeodae-gil, Seodaemun-gu, Seoul, 03760, Republic of Korea
| | - Soohyun Bae
- Clean Energy Research Center, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Byoungwoo Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Gi Soon Park
- Clean Energy Research Center, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Da Hye Won
- Clean Energy Research Center, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Dong Ki Lee
- Clean Energy Research Center, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Dong-Wook Kim
- Department of Physics, Ewha Womans University, 52, Ewhayeodae-gil, Seodaemun-gu, Seoul, 03760, Republic of Korea
| | - Tae Joo Shin
- UNIST Central Research Facilities, Ulsan National Institute of Science and Technology, 50, UNIST-gil, Ulsan, 44919, Republic of Korea
| | - Young Rag Do
- Department of Chemistry, Kookmin University, 77, Jeongneung-ro, Seongbuk-gu, Seoul, 02707, Republic of Korea
| | - Jihyun Kim
- Department of Chemical and Biological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Won Jun Choi
- Clean Energy Research Center, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Harald Ade
- Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, 851 Main Campus Dr., Raleigh, NC, 27695, USA
| | - Byoung Koun Min
- Clean Energy Research Center, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea
- Graduate School of Energy and Environment, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
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12
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Harel S, Arzel L, Lepetit T, Zabierowski P, Barreau N. Influence of Sulfur Evaporation during or after KF-Post Deposition Treatment On Cu(In,Ga)Se 2/CdS Interface Formation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:46953-46962. [PMID: 32937069 DOI: 10.1021/acsami.0c12455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This work investigates the impact of the elemental sulfur evaporation during or after KF-post deposition treatment (KF-PDT) on the resulting Cu(In,Ga)Se2/chemical bath deposited(CBD)-CdS interface. Chemical composition of the various interfaces were determined through Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray induced Auger spectroscopy (XAES). Cu(In,Ga)Se2 absorber which experienced KF-PDT in selenium atmosphere (KSe sample) exhibits the formation of the well-reported In-Se based topping layer. Additional exposure to elemental sulfur, resulting in KSe+S sample, induces the partial sulfurization of this overlayer and/or of the absorber. After short immersion into the CdS bath, the resulting In-rich surfaces of KSe and KSe+S are likely to turn into few atomic layers of Cd-In-(Se/S)-O whose [S]/[Se]+[S] ratio and O content depend on their respective post deposition treatment. In contrast, KF-PDT performed in S atmosphere does not show an In-rich surface, making the early stage of CdS growth similar to that observed on untreated CIGSe.
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Affiliation(s)
- Sylvie Harel
- CNRS, Institut des Matériaux Jean Rouxel, IMN, Université de Nantes, F-44000 Nantes, France
| | - Ludovic Arzel
- CNRS, Institut des Matériaux Jean Rouxel, IMN, Université de Nantes, F-44000 Nantes, France
| | - Thomas Lepetit
- CNRS, Institut des Matériaux Jean Rouxel, IMN, Université de Nantes, F-44000 Nantes, France
| | - Pawel Zabierowski
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warszawa, Poland
| | - Nicolas Barreau
- CNRS, Institut des Matériaux Jean Rouxel, IMN, Université de Nantes, F-44000 Nantes, France
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13
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Bombsch J, Avancini E, Carron R, Handick E, Garcia-Diez R, Hartmann C, Félix R, Ueda S, Wilks RG, Bär M. NaF/RbF-Treated Cu(In,Ga)Se 2 Thin-Film Solar Cell Absorbers: Distinct Surface Modifications Caused by Two Different Types of Rubidium Chemistry. ACS APPLIED MATERIALS & INTERFACES 2020; 12:34941-34948. [PMID: 32633119 DOI: 10.1021/acsami.0c08794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The underlying beneficial mechanism of heavy alkali postdeposition treatment (PDT) of Cu(In,Ga)Se2 thin-film solar cell absorbers that led to new record efficiencies in recent years is studied using photoelectron spectroscopy. Excitation energies between 40.8 eV and 6 keV were used to examine the near-surface region of Cu(In,Ga)Se2 thin-film solar cell absorbers that underwent NaF and combined NaF/RbF PDT. The already Cu-deficient surface region after NaF PDT, which is modeled as a Cu:(In + Ga):Se = 1:5:8 phase, shows further depletion after NaF/RbF PDT and seems to incorporate some Rb. Additionally, we have found strong indications for the NaF/RbF PDT-induced formation of a Rb-In-Se-type compound with a 1:1:2 stoichiometry partially covering the absorber surface. The electronic Cu(In,Ga)Se2 structure is modified due to the RbF treatment, with a pronounced shift in the valence band maximum away from the Fermi level in the immediate vicinity of the surface.
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Affiliation(s)
- Jakob Bombsch
- Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 14109, Germany
| | - Enrico Avancini
- Laboratory for Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland
- Now at Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano 39100, Italy
| | - Romain Carron
- Laboratory for Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland
| | - Evelyn Handick
- Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 14109, Germany
| | - Raul Garcia-Diez
- Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 14109, Germany
| | - Claudia Hartmann
- Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 14109, Germany
| | - Roberto Félix
- Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 14109, Germany
| | - Shigenori Ueda
- NIMS Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
- Research Center for Advanced Measurement and Characterization, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - Regan G Wilks
- Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 14109, Germany
- Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 12489, Germany
| | - Marcus Bär
- Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 14109, Germany
- Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 12489, Germany
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy (HI ERN), Berlin 91058, Germany
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 12489, Germany
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14
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Yang P, Wilks RG, Yang W, Bär M. Interface Formation between CdS and Alkali Postdeposition-Treated Cu(In,Ga)Se 2 Thin-Film Solar Cell Absorbers-Key To Understanding the Efficiency Gain. ACS APPLIED MATERIALS & INTERFACES 2020; 12:6688-6698. [PMID: 31912731 DOI: 10.1021/acsami.9b20327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A combination of X-ray photoelectron/Auger electron spectroscopy and soft X-ray emission spectroscopy has been employed to investigate the impact of different alkali postdeposition treatments (PDTs) on the chemical structure of the (buried) CdS/Cu(In,Ga)Se2 heterojunction: the key interface in chalcopyrite-based thin-film solar cells. Chemical bath deposited (CBD) CdS layers of different thicknesses on NaF PDT (CIGSeNaF) and NaF + KF PDT (CIGSeNaF+KF) Cu(In,Ga)Se2 absorbers prepared at low temperature (to facilitate the use of flexible, e.g., polyimide, substrates) were studied. While we find the CdS/CIGSeNaF interface to be mainly free of significant chemical interaction, in the proximity of the CdS/CIGSeNaF+KF interface, an elemental redistribution involving Cd, In, K, S, and Se is revealed. For the early stages of the CBD-CdS process, our findings are in agreement with the conversion of the K-In-Se-type layer present on the CIGSeNaF+KF surface into a mixed Cd-In-(O,OH,S,Se)-type layer, probably having some Cd-In and (S,O)-Se composition gradients. For long CBD times-independent of employed PDT-we find the buffer material to be best described by a Cd(O,OH,S)-like species rather than by a pure CdS buffer. These findings shed light on the observed performance leap of corresponding CdS/CIGSeNaF+KF-based solar cells.
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Affiliation(s)
- Penghui Yang
- Department Interface Design & Energy Materials In-Situ Laboratory Berlin (EMIL) , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin , Germany
| | - Regan G Wilks
- Department Interface Design & Energy Materials In-Situ Laboratory Berlin (EMIL) , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin , Germany
- Energy Materials In-Situ Laboratory Berlin (EMIL) , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin , Germany
| | - Wanli Yang
- Advanced Light Source Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Marcus Bär
- Department Interface Design & Energy Materials In-Situ Laboratory Berlin (EMIL) , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin , Germany
- Energy Materials In-Situ Laboratory Berlin (EMIL) , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin , Germany
- Department of Chemistry and Pharmacy , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstr. 3 , 91058 Erlangen , Germany
- Helmholtz Institute Erlangen-Nürnberg für Renewable Energy (HI ERN) , Albert-Einstein-Str. 15 , 12489 Berlin , Germany
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15
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Lee H, Jang Y, Nam SW, Jung C, Choi PP, Gwak J, Yun JH, Kim K, Shin B. Passivation of Deep-Level Defects by Cesium Fluoride Post-Deposition Treatment for Improved Device Performance of Cu(In,Ga)Se 2 Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2019; 11:35653-35660. [PMID: 31525944 DOI: 10.1021/acsami.9b08316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Heavy-alkali post-deposition treatments (PDTs) utilizing Cs or Rb has become an indispensable step in producing high-performance Cu(In,Ga)Se2 (CIGS) solar cells. However, full understanding of the mechanism behind the improvements of device performance by heavy-alkali treatments, particularly in terms of potential modification of defect characteristics, has not been reached yet. Here, we present an extensive study on the effects of CsF-PDT on material properties of CIGS absorbers and the performance of the final solar devices. Incorporation of an optimized concentration of Cs into CIGS resulted in a significant improvement of the device efficiency from 15.9 to 18.4% mainly due to an increase in the open-circuit voltage by 50 mV. Strong segregation of Cs at the front and rear interfaces as well as along grain boundaries of CIGS was observed via high-resolution chemical analysis such as atomic probe tomography. The study of defect chemistry using photoluminescence and capacitance-based measurements revealed that both deep-level donor-like defects such as VSe and InCu and deep-level acceptor-like defects such as VIn or CuIn are passivated by CsF-PDT, which contribute to an increased hole concentration. Additionally, it was found that CsF-PDT induces a slight change in the energetics of VCu, the most dominant point defect that is responsible for the p-type conductivity of CIGS.
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Affiliation(s)
- Hojin Lee
- Department of Materials Science and Engineering , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
| | - Yuseong Jang
- Department of Materials Science and Engineering , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
| | - Sung-Wook Nam
- Department of Molecular Medicine, School of Medicine , Kyungpook National University , Daegu 41404 , Republic of Korea
| | - Chanwon Jung
- Department of Materials Science and Engineering , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
| | - Pyuck-Pa Choi
- Department of Materials Science and Engineering , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
| | - Jihye Gwak
- Photovoltaic Laboratory , Korea Institute of Energy Research , Daejeon 34129 , Republic of Korea
| | - Jae Ho Yun
- Photovoltaic Laboratory , Korea Institute of Energy Research , Daejeon 34129 , Republic of Korea
| | - Kihwan Kim
- Photovoltaic Laboratory , Korea Institute of Energy Research , Daejeon 34129 , Republic of Korea
| | - Byungha Shin
- Department of Materials Science and Engineering , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
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16
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Nicoara N, Manaligod R, Jackson P, Hariskos D, Witte W, Sozzi G, Menozzi R, Sadewasser S. Direct evidence for grain boundary passivation in Cu(In,Ga)Se 2 solar cells through alkali-fluoride post-deposition treatments. Nat Commun 2019; 10:3980. [PMID: 31484943 PMCID: PMC6726603 DOI: 10.1038/s41467-019-11996-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/16/2019] [Indexed: 11/12/2022] Open
Abstract
The properties and performance of polycrystalline materials depend critically on the properties of their grain boundaries. Polycrystalline photovoltaic materials – e.g. hybrid halide perovskites, copper indium gallium diselenide (CIGSe) and cadmium telluride – have already demonstrated high efficiencies and promise cost-effective electricity supply. For CIGSe-based solar cells, an efficiency above 23% has recently been achieved using an alkali-fluoride post-deposition treatment; however, its full impact and functional principle are not yet fully understood. Here, we show direct evidence for the passivation of grain boundaries in CIGSe treated with three different alkali-fluorides through a detailed study of the nanoscale optoelectronic properties. We determine a correlation of the surface potential change at grain boundaries with the open-circuit voltage, which is supported by numerical simulations. Our results suggest that heavier alkali elements might lead to better passivation by reducing the density of charged defects and increasing the formation of secondary phases at grain boundaries. Grain boundaries play critical roles in determining the properties and performance of solar cells based on polycrystalline materials. Here Nicoara et al. showcase that proper treatments passivate defects at grain boundaries by forming secondary material phases with the CIGSe absorbers and lead to higher Voc.
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Affiliation(s)
- Nicoleta Nicoara
- International Iberian Nanotechnology Laboratory (INL), Av. Mestre José Veiga s/n, 4715-330, Braga, Portugal
| | - Roby Manaligod
- International Iberian Nanotechnology Laboratory (INL), Av. Mestre José Veiga s/n, 4715-330, Braga, Portugal
| | - Philip Jackson
- Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), Meitnerstr. 1, 70563, Stuttgart, Germany
| | - Dimitrios Hariskos
- Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), Meitnerstr. 1, 70563, Stuttgart, Germany
| | - Wolfram Witte
- Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), Meitnerstr. 1, 70563, Stuttgart, Germany
| | - Giovanna Sozzi
- Department of Engineering and Architecture, University of Parma, Parco Area delle Scienze 181A, 43124, Parma, Italy
| | - Roberto Menozzi
- Department of Engineering and Architecture, University of Parma, Parco Area delle Scienze 181A, 43124, Parma, Italy
| | - Sascha Sadewasser
- International Iberian Nanotechnology Laboratory (INL), Av. Mestre José Veiga s/n, 4715-330, Braga, Portugal.
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Weinhardt L, Hauschild D, Heske C. Surface and Interface Properties in Thin-Film Solar Cells: Using Soft X-rays and Electrons to Unravel the Electronic and Chemical Structure. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806660. [PMID: 30791138 DOI: 10.1002/adma.201806660] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 12/09/2018] [Indexed: 06/09/2023]
Abstract
Thin-film solar cells have great potential to overtake the currently dominant silicon-based solar cell technologies in a strongly growing market. Such thin-film devices consist of a multilayer structure, for which charge-carrier transport across interfaces plays a crucial role in minimizing the associated recombination losses and achieving high solar conversion efficiencies. Further development can strongly profit from a high-level characterization that gives a local, electronic, and chemical picture of the interface properties, which allows for an insight-driven optimization. Herein, the authors' recent progress of applying a "toolbox" of high-level laboratory- and synchrotron-based electron and soft X-ray spectroscopies to characterize the chemical and electronic properties of such applied interfaces is provided. With this toolbox in hand, the activities are paired with those of experts in thin-film solar cell preparation at the cutting edge of current developments to obtain a deeper understanding of the recent improvements in the field, e.g., by studying the influence of so-called "post-deposition treatments", as well as characterizing the properties of interfaces with alternative buffer layer materials that give superior efficiencies on large, module-sized areas.
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Affiliation(s)
- Lothar Weinhardt
- Institute for Photon Science and Synchrotron Radiation (IPS) and Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Department of Chemistry and Biochemistry, University of Nevada Las Vegas (UNLV), 4505 Maryland Parkway, Las Vegas, NV, 89154-4003, USA
| | - Dirk Hauschild
- Institute for Photon Science and Synchrotron Radiation (IPS) and Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Clemens Heske
- Institute for Photon Science and Synchrotron Radiation (IPS) and Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Department of Chemistry and Biochemistry, University of Nevada Las Vegas (UNLV), 4505 Maryland Parkway, Las Vegas, NV, 89154-4003, USA
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18
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Chugh M, Kühne TD, Mirhosseini H. Diffusion of Alkali Metals in Polycrystalline CuInSe 2 and Their Role in the Passivation of Grain Boundaries. ACS APPLIED MATERIALS & INTERFACES 2019; 11:14821-14829. [PMID: 30924332 DOI: 10.1021/acsami.9b02158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The behavior of alkali atom point defects in polycrystalline CuInSe2 is studied. In this work, three grain boundary models, one coherent twin boundary and two twin boundaries with dislocation cores, are considered. Total energy calculations show that all alkali metals tend to segregate at the grain boundaries. In addition, the segregation of alkali atoms is more pronounced at the grain boundaries with the dislocation cores. The diffusion of alkali metals along and near grain boundaries is studied as well. The results show that the diffusion of alkali atoms in the grain boundary models is faster than within the bulk. In addition, the ion exchange between Na and Rb atoms at the grain boundaries leads to the Rb enrichment at the grain boundaries and the increase of the Na concentration in the bulk. While the effects of Na and Rb point defects on the electronic structure of the grain boundary with the anion-core dislocation are similar, Rb atoms passivate the grain boundary with the cation-core dislocation more effectively than Na. This can explain the further improvement of the solar cell performance after the RbF-postdeposition treatment.
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Affiliation(s)
- Manjusha Chugh
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry , University of Paderborn , Warburger Str. 100 , D-33098 Paderborn , Germany
| | - Thomas D Kühne
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry , University of Paderborn , Warburger Str. 100 , D-33098 Paderborn , Germany
| | - Hossein Mirhosseini
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry , University of Paderborn , Warburger Str. 100 , D-33098 Paderborn , Germany
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19
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Kormath Madam Raghupathy R, Kühne TD, Henkelman G, Mirhosseini H. Alkali Atoms Diffusion Mechanism in CuInSe
2
Explained by Kinetic Monte Carlo Simulations. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ramya Kormath Madam Raghupathy
- Dynamics of Condensed Matter and Center for Sustainable Systems DesignChair of Theoretical ChemistryUniversity of PaderbornWarburger Str. 100 D–33098 Paderborn Germany
| | - Thomas D. Kühne
- Dynamics of Condensed Matter and Center for Sustainable Systems DesignChair of Theoretical ChemistryUniversity of PaderbornWarburger Str. 100 D–33098 Paderborn Germany
| | - Graeme Henkelman
- Department of Chemistry and the Institute for Computational Engineering and SciencesThe University of Texas at AustinAustin TX 78712‐0165 USA
| | - Hossein Mirhosseini
- Dynamics of Condensed Matter and Center for Sustainable Systems DesignChair of Theoretical ChemistryUniversity of PaderbornWarburger Str. 100 D–33098 Paderborn Germany
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20
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Malitckaya M, Kunze T, Komsa HP, Havu V, Handick E, Wilks RG, Bär M, Puska MJ. Alkali Postdeposition Treatment-Induced Changes of the Chemical and Electronic Structure of Cu(In,Ga)Se 2 Thin-Film Solar Cell Absorbers: A First-Principle Perspective. ACS APPLIED MATERIALS & INTERFACES 2019; 11:3024-3033. [PMID: 30592197 PMCID: PMC6727185 DOI: 10.1021/acsami.8b18216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 12/28/2018] [Indexed: 06/09/2023]
Abstract
The effects of alkali postdeposition treatment (PDT) on the valence band structure of Cu(In,Ga)Se2 (CIGSe) thin-film solar cell absorbers are addressed from a first-principles perspective. In detail, experimentally derived hard X-ray photoelectron spectroscopy (HAXPES) data [ Handick , E. ; ACS Appl. Mater. Interfaces 2015 , 7 , 27414 - 27420 ] of the valence band structure of alkali-free and NaF/KF-PDT CIGSe are directly compared and fit by calculated density of states (DOS) of CuInSe2, its Cu-deficient counterpart CuIn5Se8, and different potentially formed secondary phases, such as KInSe2, InSe, and In2Se3. The DOSs are based on first-principles electronic structure calculations and weighted according to element-, symmetry-, and energy-dependent photoionization cross sections for the comparison to experimental data. The HAXPES spectra were recorded using photon energies ranging from 2 to 8 keV, allowing extraction of information from different sample depths. The analysis of the alkali-free CIGSe valence band structure reveals that it can best be described by a mixture of the DOS of CuInSe2 and CuIn5Se8, resulting in a stoichiometry slightly more Cu-rich than that of CuIn3Se5. The NaF/KF-PDT-induced changes in the HAXPES spectra for different alkali exposures are best reproduced by additional contributions from KInSe2, with some indications that the formation of a pronounced K-In-Se-type surface species might crucially depend on the amount of K available during PDT.
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Affiliation(s)
- Maria Malitckaya
- Department of Applied
Physics, Aalto University, P.O. Box 11000, 00076 Aalto, Finland
| | - Thomas Kunze
- Department
of Interface Design and Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH (HZB), 12489 Berlin, Germany
| | - Hannu-Pekka Komsa
- Department of Applied
Physics, Aalto University, P.O. Box 11000, 00076 Aalto, Finland
| | - Ville Havu
- Department of Applied
Physics, Aalto University, P.O. Box 11000, 00076 Aalto, Finland
| | - Evelyn Handick
- Department
of Interface Design and Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH (HZB), 12489 Berlin, Germany
| | - Regan G. Wilks
- Department
of Interface Design and Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH (HZB), 12489 Berlin, Germany
| | - Marcus Bär
- Department
of Interface Design and Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH (HZB), 12489 Berlin, Germany
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy
(HIERN), Forschungszentrum Jülich, 90429 Erlangen, Germany
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Martti J. Puska
- Department of Applied
Physics, Aalto University, P.O. Box 11000, 00076 Aalto, Finland
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21
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Kreikemeyer-Lorenzo D, Hauschild D, Jackson P, Friedlmeier TM, Hariskos D, Blum M, Yang W, Reinert F, Powalla M, Heske C, Weinhardt L. Rubidium Fluoride Post-Deposition Treatment: Impact on the Chemical Structure of the Cu(In,Ga)Se 2 Surface and CdS/Cu(In,Ga)Se 2 Interface in Thin-Film Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2018; 10:37602-37608. [PMID: 30272438 DOI: 10.1021/acsami.8b10005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We present a detailed characterization of the chemical structure of the Cu(In,Ga)Se2 thin-film surface and the CdS/Cu(In,Ga)Se2 interface, both with and without a RbF post-deposition treatment (RbF-PDT). For this purpose, X-ray photoelectron and Auger electron spectroscopy, as well as synchrotron-based soft X-ray emission spectroscopy have been employed. Although some similarities with the reported impacts of light-element alkali PDT (i.e., NaF- and KF-PDT) are found, we observe some distinct differences, which might be the reason for the further improved conversion efficiency with heavy-element alkali PDT. In particular, we find that the RbF-PDT reduces, but not fully removes, the copper content at the absorber surface and does not induce a significant change in the Ga/(Ga + In) ratio. Additionally, we observe an increased amount of indium and gallium oxides at the surface of the treated absorber. These oxides are partly (in the case of indium) and completely (in the case of gallium) removed from the CdS/Cu(In,Ga)Se2 interface by the chemical bath deposition of the CdS buffer.
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Affiliation(s)
- Dagmar Kreikemeyer-Lorenzo
- Institute for Photon Science and Synchrotron Radiation (IPS) , Karlsruhe Institute of Technology (KIT) , Hermann-v.-Helmholtz-Platz 1 , 76344 Eggenstein-Leopoldshafen , Germany
| | - Dirk Hauschild
- Institute for Photon Science and Synchrotron Radiation (IPS) , Karlsruhe Institute of Technology (KIT) , Hermann-v.-Helmholtz-Platz 1 , 76344 Eggenstein-Leopoldshafen , Germany
- Institute for Chemical Technology and Polymer Chemistry (ITCP) , Karlsruhe Institute of Technology (KIT) , Engesserstr. 18/20 , 76128 Karlsruhe , Germany
- Experimental Physics VII , University of Würzburg , Am Hubland , 97074 Würzburg , Germany
| | - Philip Jackson
- Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW) , Meitnerstrasse 1 , 70563 Stuttgart , Germany
| | - Theresa M Friedlmeier
- Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW) , Meitnerstrasse 1 , 70563 Stuttgart , Germany
| | - Dimitrios Hariskos
- Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW) , Meitnerstrasse 1 , 70563 Stuttgart , Germany
| | - Monika Blum
- Advanced Light Source (ALS) , Lawrence Berkeley National Laboratory , One Cyclotron Road , Berkeley , 94720 California , United States
- Department of Chemistry and Biochemistry , University of Nevada, Las Vegas (UNLV) , 4505 Maryland Parkway , Las Vegas , 89154-4003 Nevada , United States
| | - Wanli Yang
- Advanced Light Source (ALS) , Lawrence Berkeley National Laboratory , One Cyclotron Road , Berkeley , 94720 California , United States
| | - Friedrich Reinert
- Experimental Physics VII , University of Würzburg , Am Hubland , 97074 Würzburg , Germany
| | - Michael Powalla
- Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW) , Meitnerstrasse 1 , 70563 Stuttgart , Germany
| | - Clemens Heske
- Institute for Photon Science and Synchrotron Radiation (IPS) , Karlsruhe Institute of Technology (KIT) , Hermann-v.-Helmholtz-Platz 1 , 76344 Eggenstein-Leopoldshafen , Germany
- Institute for Chemical Technology and Polymer Chemistry (ITCP) , Karlsruhe Institute of Technology (KIT) , Engesserstr. 18/20 , 76128 Karlsruhe , Germany
- Department of Chemistry and Biochemistry , University of Nevada, Las Vegas (UNLV) , 4505 Maryland Parkway , Las Vegas , 89154-4003 Nevada , United States
| | - Lothar Weinhardt
- Institute for Photon Science and Synchrotron Radiation (IPS) , Karlsruhe Institute of Technology (KIT) , Hermann-v.-Helmholtz-Platz 1 , 76344 Eggenstein-Leopoldshafen , Germany
- Institute for Chemical Technology and Polymer Chemistry (ITCP) , Karlsruhe Institute of Technology (KIT) , Engesserstr. 18/20 , 76128 Karlsruhe , Germany
- Department of Chemistry and Biochemistry , University of Nevada, Las Vegas (UNLV) , 4505 Maryland Parkway , Las Vegas , 89154-4003 Nevada , United States
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22
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Nicoara N, Kunze T, Jackson P, Hariskos D, Duarte RF, Wilks RG, Witte W, Bär M, Sadewasser S. Evidence for Chemical and Electronic Nonuniformities in the Formation of the Interface of RbF-Treated Cu(In,Ga)Se 2 with CdS. ACS APPLIED MATERIALS & INTERFACES 2017; 9:44173-44180. [PMID: 29178776 DOI: 10.1021/acsami.7b12448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report on the initial stages of CdS buffer layer formation on Cu(In,Ga)Se2 (CIGSe) thin-film solar cell absorbers subjected to rubidium fluoride (RbF) postdeposition treatment (PDT). A detailed characterization of the CIGSe/CdS interface for different chemical bath deposition (CBD) times of the CdS layer is obtained from spatially resolved atomic and Kelvin probe force microscopy and laterally integrating X-ray spectroscopies. The observed spatial inhomogeneity in the interface's structural, chemical, and electronic properties of samples undergoing up to 3 min of CBD treatments is indicative of a complex interface formation including an incomplete coverage and/or nonuniform composition of the buffer layer. It is expected that this result impacts solar cell performance, in particular when reducing the CdS layer thickness (e.g., in an attempt to increase the collection in the ultraviolet wavelength region). Our work provides important findings on the absorber/buffer interface formation and reveals the underlying mechanism for limitations in the reduction of the CdS thickness, even when an alkali PDT is applied to the CIGSe absorber.
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Affiliation(s)
- Nicoleta Nicoara
- International Iberian Nanotechnology Laboratory (INL) , 4715-330 Braga, Portugal
| | - Thomas Kunze
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , 14109 Berlin, Germany
| | - Philip Jackson
- Zentrum für Sonnenenergie-und Wasserstoff-Forschung Baden-Württemberg (ZSW) , 70563 Stuttgart, Germany
| | - Dimitrios Hariskos
- Zentrum für Sonnenenergie-und Wasserstoff-Forschung Baden-Württemberg (ZSW) , 70563 Stuttgart, Germany
| | - Roberto Félix Duarte
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , 14109 Berlin, Germany
| | - Regan G Wilks
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , 14109 Berlin, Germany
- Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin, Germany
| | - Wolfram Witte
- Zentrum für Sonnenenergie-und Wasserstoff-Forschung Baden-Württemberg (ZSW) , 70563 Stuttgart, Germany
| | - Marcus Bär
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , 14109 Berlin, Germany
- Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin, Germany
- Institut für Physik, Brandenburgische Technische Universität Cottbus-Senftenberg , 03046 Cottbus, Germany
| | - Sascha Sadewasser
- International Iberian Nanotechnology Laboratory (INL) , 4715-330 Braga, Portugal
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