CdCl2 passivation of polycrystalline CdMgTe and CdZnTe absorbers for tandem photovoltaic cells
Abstract
As single-junction silicon solar cells approach their theoretical limits, tandems provide the primary path to higher efficiencies. CdTe alloys can be tuned with magnesium (CdMgTe) or zinc (CdZnTe) for ideal tandem pairing with silicon. A II-VI/Si tandem holds the greatest promise for inexpensive, high-efficiency top cells that can be quickly deployed in the market using existing polycrystalline CdTe manufacturing lines combined with mature silicon production lines. Currently, all high efficiency polycrystalline CdTe cells require a chloride-based passivation process to passivate grain boundaries and bulk defects. This research examines the rich chemistry and physics that has historically limited performance when extending Cl treatments to polycrystalline 1.7-eV CdMgTe and CdZnTe absorbers. A combination of transmittance, quantum efficiency, photoluminescence, transmission electron microscopy, and energy-dispersive X-ray spectroscopy clearly reveals that during passivation, Mg segregates and out-diffuses, initially at the grain boundaries but eventually throughout the bulk. CdZnTe exhibits similar Zn segregation behavior; however, the onset and progression is localized to the back of the device. After passivation, CdMgTe and CdZnTe can render a layer that is reduced to predominantly CdTe electro-optical behavior. Furthermore, contact instabilities caused by inter-diffusion between the layers create additional complications. The results outline critical issues and paths for these materialsmore »
- Authors:
-
- Arizona State Univ., Tempe, AZ (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Colorado State Univ., Fort Collins, CO (United States)
- Loughborough Univ. (United Kingdom)
- Arizona State Univ., Tempe, AZ (United States)
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Publication Date:
- Research Org.:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Org.:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Photovoltaic Research and Development (PVRD) Program
- OSTI Identifier:
- 1456869
- Alternate Identifier(s):
- OSTI ID: 1438286
- Report Number(s):
- NREL/JA-5K00-71795
Journal ID: ISSN 0021-8979
- Grant/Contract Number:
- AC36-08GO28308; EE0007552
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Journal of Applied Physics
- Additional Journal Information:
- Journal Volume: 123; Journal Issue: 20; Journal ID: ISSN 0021-8979
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; polycrystals; luminescence; transition metals; semiconductors; solar cells; photodetectors; crystal defects; electrical engineering; band gap
Citation Formats
Swanson, Drew E., Reich, Carey, Abbas, Ali, Shimpi, Tushar, Liu, Hanxiao, Ponce, Fernando A., Walls, John M., Zhang, Yong-Hang, Metzger, Wyatt K., Sampath, W. S., and Holman, Zachary C. CdCl2 passivation of polycrystalline CdMgTe and CdZnTe absorbers for tandem photovoltaic cells. United States: N. p., 2018.
Web. doi:10.1063/1.5023811.
Swanson, Drew E., Reich, Carey, Abbas, Ali, Shimpi, Tushar, Liu, Hanxiao, Ponce, Fernando A., Walls, John M., Zhang, Yong-Hang, Metzger, Wyatt K., Sampath, W. S., & Holman, Zachary C. CdCl2 passivation of polycrystalline CdMgTe and CdZnTe absorbers for tandem photovoltaic cells. United States. https://doi.org/10.1063/1.5023811
Swanson, Drew E., Reich, Carey, Abbas, Ali, Shimpi, Tushar, Liu, Hanxiao, Ponce, Fernando A., Walls, John M., Zhang, Yong-Hang, Metzger, Wyatt K., Sampath, W. S., and Holman, Zachary C. Tue .
"CdCl2 passivation of polycrystalline CdMgTe and CdZnTe absorbers for tandem photovoltaic cells". United States. https://doi.org/10.1063/1.5023811. https://www.osti.gov/servlets/purl/1456869.
@article{osti_1456869,
title = {CdCl2 passivation of polycrystalline CdMgTe and CdZnTe absorbers for tandem photovoltaic cells},
author = {Swanson, Drew E. and Reich, Carey and Abbas, Ali and Shimpi, Tushar and Liu, Hanxiao and Ponce, Fernando A. and Walls, John M. and Zhang, Yong-Hang and Metzger, Wyatt K. and Sampath, W. S. and Holman, Zachary C.},
abstractNote = {As single-junction silicon solar cells approach their theoretical limits, tandems provide the primary path to higher efficiencies. CdTe alloys can be tuned with magnesium (CdMgTe) or zinc (CdZnTe) for ideal tandem pairing with silicon. A II-VI/Si tandem holds the greatest promise for inexpensive, high-efficiency top cells that can be quickly deployed in the market using existing polycrystalline CdTe manufacturing lines combined with mature silicon production lines. Currently, all high efficiency polycrystalline CdTe cells require a chloride-based passivation process to passivate grain boundaries and bulk defects. This research examines the rich chemistry and physics that has historically limited performance when extending Cl treatments to polycrystalline 1.7-eV CdMgTe and CdZnTe absorbers. A combination of transmittance, quantum efficiency, photoluminescence, transmission electron microscopy, and energy-dispersive X-ray spectroscopy clearly reveals that during passivation, Mg segregates and out-diffuses, initially at the grain boundaries but eventually throughout the bulk. CdZnTe exhibits similar Zn segregation behavior; however, the onset and progression is localized to the back of the device. After passivation, CdMgTe and CdZnTe can render a layer that is reduced to predominantly CdTe electro-optical behavior. Furthermore, contact instabilities caused by inter-diffusion between the layers create additional complications. The results outline critical issues and paths for these materials to be successfully implemented in Si-based tandems and other applications.},
doi = {10.1063/1.5023811},
journal = {Journal of Applied Physics},
number = 20,
volume = 123,
place = {United States},
year = {2018},
month = {5}
}
Web of Science
Works referenced in this record:
3D Lifetime Tomography Reveals How CdCl 2 Improves Recombination Throughout CdTe Solar Cells
journal, November 2016
- Barnard, Edward S.; Ursprung, Benedikt; Colegrove, Eric
- Advanced Materials, Vol. 29, Issue 3
Incorporation of Cd 1-x Mg x Te as an Electron Reflector for Cadmium Telluride Photovoltaic Cells
journal, January 2015
- Swanson, Drew E.; Abbas, Ali; Munshi, Amit H.
- MRS Proceedings, Vol. 1771
Identification of critical stacking faults in thin-film CdTe solar cells
journal, August 2014
- Yoo, Su-Hyun; Butler, Keith T.; Soon, Aloysius
- Applied Physics Letters, Vol. 105, Issue 6
Energy-yield prediction for II–VI-based thin-film tandem solar cells
journal, January 2016
- Mailoa, Jonathan P.; Lee, Mitchell; Peters, Ian M.
- Energy & Environmental Science, Vol. 9, Issue 8
The potential and device physics of interdigitated thin-film solar cells
journal, May 2008
- Metzger, Wyatt K.
- Journal of Applied Physics, Vol. 103, Issue 9
Monocrystalline CdTe solar cells with open-circuit voltage over 1 V and efficiency of 17%
journal, May 2016
- Zhao, Yuan; Boccard, Mathieu; Liu, Shi
- Nature Energy, Vol. 1, Issue 6
Grain-Boundary-Enhanced Carrier Collection in CdTe Solar Cells
journal, April 2014
- Li, Chen; Wu, Yelong; Poplawsky, Jonathan
- Physical Review Letters, Vol. 112, Issue 15
Growth and process optimization of CdTe and CdZnTe polycrystalline films for high efficiency solar cells
journal, May 1991
- Rohatgi, A.; Sudharsanan, R.; Ringel, S. A.
- Solar Cells, Vol. 30, Issue 1-4
Emitter/absorber interface of CdTe solar cells
journal, June 2016
- Song, Tao; Kanevce, Ana; Sites, James R.
- Journal of Applied Physics, Vol. 119, Issue 23
Charged grain boundaries reduce the open-circuit voltage of polycrystalline solar cells—An analytical description
journal, December 2016
- Gaury, Benoit; Haney, Paul M.
- Journal of Applied Physics, Vol. 120, Issue 23
Low-Cost CdTe/Silicon Tandem Solar Cells
journal, November 2017
- Tamboli, Adele C.; Bobela, David C.; Kanevce, Ana
- IEEE Journal of Photovoltaics, Vol. 7, Issue 6
Co-sublimation of CdSexTe1−x layers for CdTe solar cells
journal, January 2017
- Swanson, Drew E.; Sites, James R.; Sampath, Walajabad S.
- Solar Energy Materials and Solar Cells, Vol. 159
Solar cell efficiency tables (version 50)
journal, June 2017
- Green, Martin A.; Hishikawa, Yoshihiro; Warta, Wilhelm
- Progress in Photovoltaics: Research and Applications, Vol. 25, Issue 7
Single-crystal II-VI on Si single-junction and tandem solar cells
journal, April 2010
- Carmody, M.; Mallick, S.; Margetis, J.
- Applied Physics Letters, Vol. 96, Issue 15
A review of thin film solar cell technologies and challenges
journal, April 2017
- Lee, Taesoo D.; Ebong, Abasifreke U.
- Renewable and Sustainable Energy Reviews, Vol. 70
Effect of the cadmium chloride treatment on RF sputtered Cd 0.6 Zn 0.4 Te films for application in multijunction solar cells
journal, September 2016
- Shimpi, Tushar M.; Kephart, Jason M.; Swanson, Drew E.
- Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, Vol. 34, Issue 5
Raising the one-sun conversion efficiency of III–V/Si solar cells to 32.8% for two junctions and 35.9% for three junctions
journal, August 2017
- Essig, Stephanie; Allebé, Christophe; Remo, Timothy
- Nature Energy, Vol. 2, Issue 9
Selecting tandem partners for silicon solar cells
journal, September 2016
- Yu, Zhengshan; Leilaeioun, Mehdi; Holman, Zachary
- Nature Energy, Vol. 1, Issue 11
A low-cost non-toxic post-growth activation step for CdTe solar cells
journal, June 2014
- Major, J. D.; Treharne, R. E.; Phillips, L. J.
- Nature, Vol. 511, Issue 7509
Deposition and characterization of Cd 1−x Mg x Te thin films grown by a novel cosublimation method
journal, March 2014
- Kobyakov, Pavel S.; Moore, Andrew; Raguse, John M.
- Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, Vol. 32, Issue 2
Detailed Balance Limit of Efficiency of p‐n Junction Solar Cells
journal, March 1961
- Shockley, William; Queisser, Hans J.
- Journal of Applied Physics, Vol. 32, Issue 3, p. 510-519
Grain-boundary recombination in Cu(In,Ga)Se2 solar cells
journal, December 2005
- Gloeckler, Markus; Sites, James R.; Metzger, Wyatt K.
- Journal of Applied Physics, Vol. 98, Issue 11
Improved CdTe Solar-Cell Performance with An Evaporated Te Layer before The Back Contact
journal, January 2017
- Moore, Andrew; Song, Tao; Sites, James
- MRS Advances, Vol. 2, Issue 53
Single vacuum chamber with multiple close space sublimation sources to fabricate CdTe solar cells
journal, February 2016
- Swanson, Drew E.; Kephart, Jason M.; Kobyakov, Pavel S.
- Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, Vol. 34, Issue 2
The impact of charged grain boundaries on thin-film solar cells and characterization
journal, September 2005
- Metzger, W. K.; Gloeckler, M.
- Journal of Applied Physics, Vol. 98, Issue 6
Techno-economic analysis of tandem photovoltaic systems
journal, January 2016
- Peters, I. M.; Sofia, S.; Mailoa, J.
- RSC Advances, Vol. 6, Issue 71
Band alignment of front contact layers for high-efficiency CdTe solar cells
journal, December 2016
- Kephart, J. M.; McCamy, J. W.; Ma, Z.
- Solar Energy Materials and Solar Cells, Vol. 157
Optical properties and electronic structure of amorphous Ge and Si
journal, January 1968
- Tauc, J.
- Materials Research Bulletin, Vol. 3, Issue 1
Charged grain boundaries reduce the open circuit voltage of polycrystalline solar cells--An analytical description
text, January 2016
- Gaury, Benoit; Haney, Paul M.
- arXiv