Back-surface recombination, electron reflectors, and paths to 28% efficiency for thin-film photovoltaics: A CdTe case study
Abstract
As thin-film and silicon solar technologies mature, questions emerge about the upper bounds of thin-film solar performance and realistic experimental paths to reach them. Directions include increasing absorber hole density and bulk lifetime, improving the junction interface, reducing back-surface recombination, and implementing a back-surface electron reflector. Textbook solutions of idealized p-n junctions create a powerful conceptualization of solar cells as predominantly minority-carrier-driven devices. We demonstrate that thin films are distinct, and models often fail to capture the important role of majority-carrier lifetime, leading to contradictions with lifetime measurements and overestimates of potential device improvement from back-surface passivation and/or reflectors. Furthermore, we identify methods to probe majority-carrier lifetime and re-examine the degree to which back-surface passivation and electron reflectors can increase efficiency for a range of common thin-film interface and absorber properties, using current and emerging CdTe technology as an example. Here, the results indicate that a practical approach is to focus first on improving front-interface recombination velocity and the absorber properties, and then on implementing the back-surface passivation or reflector, which can ultimately allow thin-film solar technology to reach 28% efficiency.
- Authors:
-
- 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), Renewable Power Office. Solar Energy Technologies Office
- OSTI Identifier:
- 1494117
- Report Number(s):
- NREL/JA-5K00-73045
Journal ID: ISSN 0021-8979
- Grant/Contract Number:
- AC36-08GO28308
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Journal of Applied Physics
- Additional Journal Information:
- Journal Volume: 125; Journal Issue: 5; Journal ID: ISSN 0021-8979
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 14 SOLAR ENERGY; 36 MATERIALS SCIENCE; CdTe; lifetime; back surface recombination; electron reflector
Citation Formats
Duenow, Joel N., and Metzger, Wyatt K. Back-surface recombination, electron reflectors, and paths to 28% efficiency for thin-film photovoltaics: A CdTe case study. United States: N. p., 2019.
Web. doi:10.1063/1.5063799.
Duenow, Joel N., & Metzger, Wyatt K. Back-surface recombination, electron reflectors, and paths to 28% efficiency for thin-film photovoltaics: A CdTe case study. United States. https://doi.org/10.1063/1.5063799
Duenow, Joel N., and Metzger, Wyatt K. Fri .
"Back-surface recombination, electron reflectors, and paths to 28% efficiency for thin-film photovoltaics: A CdTe case study". United States. https://doi.org/10.1063/1.5063799. https://www.osti.gov/servlets/purl/1494117.
@article{osti_1494117,
title = {Back-surface recombination, electron reflectors, and paths to 28% efficiency for thin-film photovoltaics: A CdTe case study},
author = {Duenow, Joel N. and Metzger, Wyatt K.},
abstractNote = {As thin-film and silicon solar technologies mature, questions emerge about the upper bounds of thin-film solar performance and realistic experimental paths to reach them. Directions include increasing absorber hole density and bulk lifetime, improving the junction interface, reducing back-surface recombination, and implementing a back-surface electron reflector. Textbook solutions of idealized p-n junctions create a powerful conceptualization of solar cells as predominantly minority-carrier-driven devices. We demonstrate that thin films are distinct, and models often fail to capture the important role of majority-carrier lifetime, leading to contradictions with lifetime measurements and overestimates of potential device improvement from back-surface passivation and/or reflectors. Furthermore, we identify methods to probe majority-carrier lifetime and re-examine the degree to which back-surface passivation and electron reflectors can increase efficiency for a range of common thin-film interface and absorber properties, using current and emerging CdTe technology as an example. Here, the results indicate that a practical approach is to focus first on improving front-interface recombination velocity and the absorber properties, and then on implementing the back-surface passivation or reflector, which can ultimately allow thin-film solar technology to reach 28% efficiency.},
doi = {10.1063/1.5063799},
journal = {Journal of Applied Physics},
number = 5,
volume = 125,
place = {United States},
year = {2019},
month = {2}
}
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Works referenced in this record:
Energy-band barrier to improve open-circuit voltage of CdTe solar cells
journal, January 2014
- Hsiao, Kuo-Jui
- Solar Energy Materials and Solar Cells, Vol. 120
Carrier generation-recombination in the space-charge region of an asymmetrical p-n junction
journal, November 1968
- Choo, S. C.
- Solid-State Electronics, Vol. 11, Issue 11
Single-crystal CdTe solar cells with V oc greater than 900 mV
journal, August 2014
- Duenow, J. N.; Burst, J. M.; Albin, D. S.
- Applied Physics Letters, Vol. 105, Issue 5
Strategies to increase CdTe solar-cell voltage
journal, May 2007
- Sites, James; Pan, Jun
- Thin Solid Films, Vol. 515, Issue 15, p. 6099-6102
Modelling polycrystalline semiconductor solar cells
journal, February 2000
- Burgelman, M.; Nollet, P.; Degrave, S.
- Thin Solid Films, Vol. 361-362
Hole current impedance and electron current enhancement by back-contact barriers in CdTe thin film solar cells
journal, December 2006
- Pan, Jun; Gloeckler, Markus; Sites, James R.
- Journal of Applied Physics, Vol. 100, Issue 12
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
Surface Passivation of CdTe Single Crystals
journal, January 2015
- Reese, Matthew O.; Burst, James M.; Perkins, Craig L.
- IEEE Journal of Photovoltaics, Vol. 5, Issue 1
Experimental and theoretical comparison of Sb, As, and P diffusion mechanisms and doping in CdTe
journal, January 2018
- Colegrove, E.; Yang, J-H; Harvey, S. P.
- Journal of Physics D: Applied Physics, Vol. 51, Issue 7
Overcoming Carrier Concentration Limits in Polycrystalline CdTe Thin Films with In Situ Doping
journal, September 2018
- McCandless, Brian E.; Buchanan, Wayne A.; Thompson, Christopher P.
- Scientific Reports, Vol. 8, Issue 1
Sputter-Deposited Oxides for Interface Passivation of CdTe Photovoltaics
journal, March 2018
- Kephart, Jason M.; Kindvall, Anna; Williams, Desiree
- IEEE Journal of Photovoltaics, Vol. 8, Issue 2
Relationship of Open-Circuit Voltage to CdTe Hole Concentration and Lifetime
journal, November 2016
- Duenow, Joel N.; Burst, James M.; Albin, David S.
- IEEE Journal of Photovoltaics, Vol. 6, Issue 6
Statistics of the Recombinations of Holes and Electrons
journal, September 1952
- Shockley, W.; Read, W. T.
- Physical Review, Vol. 87, Issue 5
Intrinsic surface passivation of CdTe
journal, October 2015
- Reese, M. O.; Perkins, C. L.; Burst, J. M.
- Journal of Applied Physics, Vol. 118, Issue 15
Recombination velocity less than 100 cm/s at polycrystalline Al 2 O 3 /CdSeTe interfaces
journal, June 2018
- Kuciauskas, Darius; Kephart, Jason M.; Moseley, John
- Applied Physics Letters, Vol. 112, Issue 26
High growth rate hydride vapor phase epitaxy at low temperature through use of uncracked hydrides
journal, January 2018
- Schulte, Kevin L.; Braun, Anna; Simon, John
- Applied Physics Letters, Vol. 112, Issue 4
The roles of carrier concentration and interface, bulk, and grain-boundary recombination for 25% efficient CdTe solar cells
journal, June 2017
- Kanevce, A.; Reese, M. O.; Barnes, T. M.
- Journal of Applied Physics, Vol. 121, Issue 21
Influence of CdTe Deposition Temperature and Window Thickness on CdTe Grain Size and Lifetime After CdCl 2 Recrystallization
journal, March 2018
- Amarasinghe, Mahisha; Sivananthan, Siva; Metzger, Wyatt K.
- IEEE Journal of Photovoltaics, Vol. 8, Issue 2
Obtaining Large Columnar CdTe Grains and Long Lifetime on Nanocrystalline CdSe, MgZnO, or CdS Layers
journal, January 2018
- Amarasinghe, Mahisha; Colegrove, Eric; Moseley, John
- Advanced Energy Materials, Vol. 8, Issue 11
Time-resolved photoluminescence studies of CdTe solar cells
journal, September 2003
- Metzger, W. K.; Albin, D.; Levi, D.
- Journal of Applied Physics, Vol. 94, Issue 5, p. 3549-3555
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
Cu2ZnSnS4 solar cells with over 10% power conversion efficiency enabled by heterojunction heat treatment
journal, July 2018
- Yan, Chang; Huang, Jialiang; Sun, Kaiwen
- Nature Energy, Vol. 3, Issue 9
Electron-Hole Diffusion Lengths Exceeding 1 Micrometer in an Organometal Trihalide Perovskite Absorber
journal, October 2013
- Stranks, S. D.; Eperon, G. E.; Grancini, G.
- Science, Vol. 342, Issue 6156, p. 341-344
Enhancing the photo-currents of CdTe thin-film solar cells in both short and long wavelength regions
journal, November 2014
- Paudel, Naba R.; Yan, Yanfa
- Applied Physics Letters, Vol. 105, Issue 18
Solar cell efficiency tables (version 52)
journal, June 2018
- Green, Martin A.; Hishikawa, Yoshihiro; Dunlop, Ewan D.
- Progress in Photovoltaics: Research and Applications, Vol. 26, Issue 7
CdTe solar cells with open-circuit voltage breaking the 1 V barrier
journal, February 2016
- Burst, J. M.; Duenow, J. N.; Albin, D. S.
- Nature Energy, Vol. 1, Issue 3
Carrier density and lifetime for different dopants in single-crystal and polycrystalline CdTe
journal, November 2016
- Burst, James M.; Farrell, Stuart B.; Albin, David S.
- APL Materials, Vol. 4, Issue 11
Electron-Hole Recombination in Germanium
journal, July 1952
- Hall, R. N.
- Physical Review, Vol. 87, Issue 2
Analysis of charge separation dynamics in a semiconductor junction
journal, January 2005
- Metzger, W. K.; Ahrenkiel, R. K.; Dashdorj, J.
- Physical Review B, Vol. 71, Issue 3
Carrier Generation and Recombination in P-N Junctions and P-N Junction Characteristics
journal, September 1957
- Sah, Chih-tang; Noyce, Robert; Shockley, William
- Proceedings of the IRE, Vol. 45, Issue 9
Long lifetimes in high-efficiency Cu(In,Ga)Se2 solar cells
journal, July 2008
- Metzger, Wyatt K.; Repins, Ingrid L.; Contreras, Miguel A.
- Applied Physics Letters, Vol. 93, Issue 2
CdTe Solar Cells at the Threshold to 20% Efficiency
journal, October 2013
- Gloeckler, M.; Sankin, I.; Zhao, Z.
- IEEE Journal of Photovoltaics, Vol. 3, Issue 4
Polycrystalline CdSeTe/CdTe Absorber Cells With 28 mA/cm 2 Short-Circuit Current
journal, January 2018
- Munshi, Amit H.; Kephart, Jason; Abbas, Ali
- IEEE Journal of Photovoltaics, Vol. 8, Issue 1
Works referencing / citing this record:
Exceeding 20% efficiency with in situ group V doping in polycrystalline CdTe solar cells
journal, August 2019
- Metzger, W. K.; Grover, S.; Lu, D.
- Nature Energy, Vol. 4, Issue 10
Light-trapping schemes for silicon thin-film solar cells via super-quadratic subwavelength gratings
journal, January 2019
- Chen, Ke; Wu, Rui; Zheng, Hongmei
- Applied Optics, Vol. 58, Issue 31