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Title: Design of Integrated III-Nitride/Non-III-Nitride Tandem Photovoltaic Devices

Abstract

The integration of III-nitride and non-III-nitride materials for tandem solar cell applications can improve the efficiency of the photovoltaic device due to the added power contributed by the III-nitride top cell to that of high-efficiency multi-junction non-III-nitride solar cells if the device components are properly designed and optimized. The proposed tandem solar cell is comprised of a III-nitride top cell bonded to a non-III-nitride, series-constrained, multi-junction subcell. The top cell is electrically isolated, but optically coupled to the underlying subcell. The use of a III-nitride top cell is potentially beneficial when the top junction of a stand-alone non-III-nitride subcell generates more photocurrent than the limiting current of the non-III-nitride subcell. Light producing this excess current can either be redirected to the III-nitride top cell through high energy photon absorption, redirected to the lower junctions through layer thickness optimization, or a combination of both, resulting in improved total efficiency. When the non-III-nitride cell's top junction is the limiting junction, the minimum power conversion efficiency that the III-nitride top cell must contribute should compensate for the spectrum filtered from the multi-junction subcell for this design to be useful. As the III-nitride absorption edge wavelength, {lambda}{sub N}, increases, the performance of the multi-junctionmore » subcell decreases due to spectral filtering. In the most common spectra of interest (AM1.5G, AM1.5 D, and AM0), the technology to grow InGaN cells with {lambda}{sub N}<520 nm is found to be sufficient for III-nitride top cell applications. The external quantum efficiency performance, however, of state-of-the-art InGaN solar cells still needs to be improved. The effects of surface/interface reflections are also presented. The management of these reflection issues determines the feasibility of the integrated III-nitride/non-III-nitride design to improve overall cell efficiency.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy Solar Energy Technologies Program
OSTI Identifier:
1047345
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 111; Journal Issue: 5; Related Information: Article No. 054503; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; ABSORPTION; CONVERSION; DESIGN; EFFICIENCY; GALLIUM NITRIDES; INDIUM NITRIDES; LAYERS; MATERIALS; OPTIMIZATION; PERFORMANCE; PHOTOCURRENTS; PHOTONS; POWER; QUANTUM EFFICIENCY; REFLECTION; SEMICONDUCTOR MATERIALS; SOLAR CELLS; SPECTRA; THICKNESS; USES; VISIBLE RADIATION; Solar Energy - Photovoltaics

Citation Formats

Toledo, N. G., Friedman, D..J., Farrell, R. M., Perl, E. E., Lin, C. T., Bowers, J. E., Speck, J. S., and Mishra, U. K. Design of Integrated III-Nitride/Non-III-Nitride Tandem Photovoltaic Devices. United States: N. p., 2012. Web. doi:10.1063/1.3690907.
Toledo, N. G., Friedman, D..J., Farrell, R. M., Perl, E. E., Lin, C. T., Bowers, J. E., Speck, J. S., & Mishra, U. K. Design of Integrated III-Nitride/Non-III-Nitride Tandem Photovoltaic Devices. United States. doi:10.1063/1.3690907.
Toledo, N. G., Friedman, D..J., Farrell, R. M., Perl, E. E., Lin, C. T., Bowers, J. E., Speck, J. S., and Mishra, U. K. Thu . "Design of Integrated III-Nitride/Non-III-Nitride Tandem Photovoltaic Devices". United States. doi:10.1063/1.3690907.
@article{osti_1047345,
title = {Design of Integrated III-Nitride/Non-III-Nitride Tandem Photovoltaic Devices},
author = {Toledo, N. G. and Friedman, D..J. and Farrell, R. M. and Perl, E. E. and Lin, C. T. and Bowers, J. E. and Speck, J. S. and Mishra, U. K.},
abstractNote = {The integration of III-nitride and non-III-nitride materials for tandem solar cell applications can improve the efficiency of the photovoltaic device due to the added power contributed by the III-nitride top cell to that of high-efficiency multi-junction non-III-nitride solar cells if the device components are properly designed and optimized. The proposed tandem solar cell is comprised of a III-nitride top cell bonded to a non-III-nitride, series-constrained, multi-junction subcell. The top cell is electrically isolated, but optically coupled to the underlying subcell. The use of a III-nitride top cell is potentially beneficial when the top junction of a stand-alone non-III-nitride subcell generates more photocurrent than the limiting current of the non-III-nitride subcell. Light producing this excess current can either be redirected to the III-nitride top cell through high energy photon absorption, redirected to the lower junctions through layer thickness optimization, or a combination of both, resulting in improved total efficiency. When the non-III-nitride cell's top junction is the limiting junction, the minimum power conversion efficiency that the III-nitride top cell must contribute should compensate for the spectrum filtered from the multi-junction subcell for this design to be useful. As the III-nitride absorption edge wavelength, {lambda}{sub N}, increases, the performance of the multi-junction subcell decreases due to spectral filtering. In the most common spectra of interest (AM1.5G, AM1.5 D, and AM0), the technology to grow InGaN cells with {lambda}{sub N}<520 nm is found to be sufficient for III-nitride top cell applications. The external quantum efficiency performance, however, of state-of-the-art InGaN solar cells still needs to be improved. The effects of surface/interface reflections are also presented. The management of these reflection issues determines the feasibility of the integrated III-nitride/non-III-nitride design to improve overall cell efficiency.},
doi = {10.1063/1.3690907},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 5,
volume = 111,
place = {United States},
year = {2012},
month = {3}
}