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Title: Hybrid dielectric light trapping designs for thin-film CdZnTe/Si tandem cells

Tandem solar cells consisting of high bandgap cadmium telluride alloys atop crystalline silicon have potential for high efficiencies exceeding the Shockley-Queisser limit. However, experimental results have fallen well below this goal significantly because of non-ideal current matching and light trapping. In this work, we simulate cadmium zinc telluride (CZT) and crystalline silicon (c-Si) tandems as an exemplary system to show the role that a hybrid light trapping and bandgap engineering approach can play in improving performance and lowering materials costs for tandem solar cells incorporating crystalline silicon. This work consists of two steps. First, we optimize absorption in the crystalline silicon layer with front pyramidal texturing and asymmetric dielectric back gratings, which results in 121% absorption enhancement from a planar structure. Then, using this pre-optimized light trapping scheme, we model the dispersion of the Cd xZn 1-xTe alloys, and then adjust the bandgap to realize the best current matching for a range of CZT thicknesses. Using experimental parameters, the corresponding maximum efficiency is predicted to be 16.08 % for a total tandem cell thickness of only 2.2 μm.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [1]
  1. Purdue Univ., West Lafayette, IN (United States). School of Electrical & Computer Engineering
  2. Hanyang Univ., Seoul (Korea, Republic of). Dept. of Electronic Engineering
Publication Date:
Grant/Contract Number:
EE0004946; 2014R1A1A205440
Type:
Accepted Manuscript
Journal Name:
Optics Express
Additional Journal Information:
Journal Volume: 24; Journal Issue: 14; Journal ID: ISSN 1094-4087
Publisher:
Optical Society of America (OSA)
Research Org:
Purdue Univ., West Lafayette, IN (United States); Hanyang Univ., Seoul (Korea, Republic of)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S); National Research Foundation of Korea (NRF)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; refractive index; resonant modes; semiconductors; solar energy; surface plasmon polaritons; tandem solar cells
OSTI Identifier:
1437640

Chung, H., Zhou, C., Tee, X. T., Jung, K. -Y., and Bermel, P.. Hybrid dielectric light trapping designs for thin-film CdZnTe/Si tandem cells. United States: N. p., Web. doi:10.1364/OE.24.0A1008.
Chung, H., Zhou, C., Tee, X. T., Jung, K. -Y., & Bermel, P.. Hybrid dielectric light trapping designs for thin-film CdZnTe/Si tandem cells. United States. doi:10.1364/OE.24.0A1008.
Chung, H., Zhou, C., Tee, X. T., Jung, K. -Y., and Bermel, P.. 2016. "Hybrid dielectric light trapping designs for thin-film CdZnTe/Si tandem cells". United States. doi:10.1364/OE.24.0A1008. https://www.osti.gov/servlets/purl/1437640.
@article{osti_1437640,
title = {Hybrid dielectric light trapping designs for thin-film CdZnTe/Si tandem cells},
author = {Chung, H. and Zhou, C. and Tee, X. T. and Jung, K. -Y. and Bermel, P.},
abstractNote = {Tandem solar cells consisting of high bandgap cadmium telluride alloys atop crystalline silicon have potential for high efficiencies exceeding the Shockley-Queisser limit. However, experimental results have fallen well below this goal significantly because of non-ideal current matching and light trapping. In this work, we simulate cadmium zinc telluride (CZT) and crystalline silicon (c-Si) tandems as an exemplary system to show the role that a hybrid light trapping and bandgap engineering approach can play in improving performance and lowering materials costs for tandem solar cells incorporating crystalline silicon. This work consists of two steps. First, we optimize absorption in the crystalline silicon layer with front pyramidal texturing and asymmetric dielectric back gratings, which results in 121% absorption enhancement from a planar structure. Then, using this pre-optimized light trapping scheme, we model the dispersion of the CdxZn1-xTe alloys, and then adjust the bandgap to realize the best current matching for a range of CZT thicknesses. Using experimental parameters, the corresponding maximum efficiency is predicted to be 16.08 % for a total tandem cell thickness of only 2.2 μm.},
doi = {10.1364/OE.24.0A1008},
journal = {Optics Express},
number = 14,
volume = 24,
place = {United States},
year = {2016},
month = {5}
}