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Title: Beyond the Lambertian limit: Novel low-symmetry gratings for ultimate light trapping enhancement in next-generation photovoltaics

Abstract

This project aims at addressing the efficiency limit and high fabrication cost of current light trapping methods by developing novel low-symmetry gratings (LSG) for next-generation thin c-Si photovoltaic (PV) cells. The LSG design achieves light trapping enhancement exceeding the 4n 2 Lambertian limit and can be fabricated over large areas using low-cost, single-step nanoimprint techniques. We further explored the use of deposited high-refractive-index glass materials for low-temperature LSG processing, which enables direct imprint sculpting of even complex grating geometries in glass without requiring an additional pattern transfer step, which minimizes processing cost and surface damage to PV cells. In the project, we have demonstrated fabrication and integration of sub-wavelength LSG with thin c-Si wafers and bifacial solar cells with low defect density. Optical absorption measurements indicate that LSGs demonstrated superior absorption enhancement compared to their traditional symmetric counterparts as predicted by our simulations. Efficiency enhancement was observed in solar cells integrated with LSGs although fabrication yield of the LSG-integrated cells remains a challenge

Authors:
 [1];  [1];  [2]
  1. Univ. of Delaware, Newark, DE (United States)
  2. Univ. of Central Florida, Orlando, FL (United States). College of Optics and Photonics, Center for Research and Education in Optics and Lasers (CREOL)
Publication Date:
Research Org.:
Univ. of Delaware, Newark, DE (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1419008
Report Number(s):
DOE-UDEL-0005327
DOE Contract Number:  
EE0005327
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; Lambertian limit; low-symmetry gratings; light trapping; photovoltaics

Citation Formats

Birkmire, Robert, Hu, Juejun, and Richardson, Kathleen. Beyond the Lambertian limit: Novel low-symmetry gratings for ultimate light trapping enhancement in next-generation photovoltaics. United States: N. p., 2016. Web. doi:10.2172/1419008.
Birkmire, Robert, Hu, Juejun, & Richardson, Kathleen. Beyond the Lambertian limit: Novel low-symmetry gratings for ultimate light trapping enhancement in next-generation photovoltaics. United States. doi:10.2172/1419008.
Birkmire, Robert, Hu, Juejun, and Richardson, Kathleen. Fri . "Beyond the Lambertian limit: Novel low-symmetry gratings for ultimate light trapping enhancement in next-generation photovoltaics". United States. doi:10.2172/1419008. https://www.osti.gov/servlets/purl/1419008.
@article{osti_1419008,
title = {Beyond the Lambertian limit: Novel low-symmetry gratings for ultimate light trapping enhancement in next-generation photovoltaics},
author = {Birkmire, Robert and Hu, Juejun and Richardson, Kathleen},
abstractNote = {This project aims at addressing the efficiency limit and high fabrication cost of current light trapping methods by developing novel low-symmetry gratings (LSG) for next-generation thin c-Si photovoltaic (PV) cells. The LSG design achieves light trapping enhancement exceeding the 4n2 Lambertian limit and can be fabricated over large areas using low-cost, single-step nanoimprint techniques. We further explored the use of deposited high-refractive-index glass materials for low-temperature LSG processing, which enables direct imprint sculpting of even complex grating geometries in glass without requiring an additional pattern transfer step, which minimizes processing cost and surface damage to PV cells. In the project, we have demonstrated fabrication and integration of sub-wavelength LSG with thin c-Si wafers and bifacial solar cells with low defect density. Optical absorption measurements indicate that LSGs demonstrated superior absorption enhancement compared to their traditional symmetric counterparts as predicted by our simulations. Efficiency enhancement was observed in solar cells integrated with LSGs although fabrication yield of the LSG-integrated cells remains a challenge},
doi = {10.2172/1419008},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2016},
month = {5}
}