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Title: Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique

Abstract

Excess carrier lifetime plays a crucial role in determining the efficiency of solar cells. In this paper, we use the frequency dependence of inphase and quadrature components of modulated electroluminescence (MEL) to measure the relaxation time (decay) of excess carriers. The advantage of the MEL technique is that the relaxation time is obtained directly from the angular frequency at which the quadrature component peaks. It does not need knowledge of the material parameters like mobility, etc., and can be used for any finished solar cells which have detectable light emission. The experiment is easy to perform with standard electrical equipment. For silicon solar cells, the relaxation time is dominated by recombination and hence, the relaxation time is indeed the excess carrier lifetime. In contrast, for the CIGS solar cells investigated here, the relaxation time is dominated by trapping and emission from shallow minority carrier traps.

Authors:
 [1];  [1];  [2];  [2];  [1];  [1];  [1];  [3];  [1]
  1. Indian Inst. of Technology (IIT), Mumbai (India)
  2. MoserBaer Photovoltaic Pvt. Ltd., Greater Noida (India)
  3. 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)
OSTI Identifier:
1422880
Alternate Identifier(s):
OSTI ID: 1408251
Report Number(s):
NREL/JA-5K00-70995
Journal ID: ISSN 1862-6300
Grant/Contract Number:  
AC36-08GO28308; IUSSTF/JCERDCSERIIUS/2012
Resource Type:
Accepted Manuscript
Journal Name:
Physica Status Solidi. A, Applications and Materials Science
Additional Journal Information:
Journal Volume: 215; Journal Issue: 2; Journal ID: ISSN 1862-6300
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; CIGS solar cells; frequency dependence; modulated electroluminescence; relaxation time; Si-HJ solar cells

Citation Formats

Khatavkar, Sanchit, Muniappan, Kulasekaran, Kannan, Chinna V., Kumar, Vijay, Narsimhan, Krishnamachari L., Nair, Pradeep R., Vasi, Juzer M., Contreras, Miguel A., and Arora, Brij M. Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique. United States: N. p., 2017. Web. doi:10.1002/pssa.201700267.
Khatavkar, Sanchit, Muniappan, Kulasekaran, Kannan, Chinna V., Kumar, Vijay, Narsimhan, Krishnamachari L., Nair, Pradeep R., Vasi, Juzer M., Contreras, Miguel A., & Arora, Brij M. Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique. United States. doi:10.1002/pssa.201700267.
Khatavkar, Sanchit, Muniappan, Kulasekaran, Kannan, Chinna V., Kumar, Vijay, Narsimhan, Krishnamachari L., Nair, Pradeep R., Vasi, Juzer M., Contreras, Miguel A., and Arora, Brij M. Fri . "Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique". United States. doi:10.1002/pssa.201700267. https://www.osti.gov/servlets/purl/1422880.
@article{osti_1422880,
title = {Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique},
author = {Khatavkar, Sanchit and Muniappan, Kulasekaran and Kannan, Chinna V. and Kumar, Vijay and Narsimhan, Krishnamachari L. and Nair, Pradeep R. and Vasi, Juzer M. and Contreras, Miguel A. and Arora, Brij M.},
abstractNote = {Excess carrier lifetime plays a crucial role in determining the efficiency of solar cells. In this paper, we use the frequency dependence of inphase and quadrature components of modulated electroluminescence (MEL) to measure the relaxation time (decay) of excess carriers. The advantage of the MEL technique is that the relaxation time is obtained directly from the angular frequency at which the quadrature component peaks. It does not need knowledge of the material parameters like mobility, etc., and can be used for any finished solar cells which have detectable light emission. The experiment is easy to perform with standard electrical equipment. For silicon solar cells, the relaxation time is dominated by recombination and hence, the relaxation time is indeed the excess carrier lifetime. In contrast, for the CIGS solar cells investigated here, the relaxation time is dominated by trapping and emission from shallow minority carrier traps.},
doi = {10.1002/pssa.201700267},
journal = {Physica Status Solidi. A, Applications and Materials Science},
number = 2,
volume = 215,
place = {United States},
year = {2017},
month = {11}
}

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