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Journal of Nanomaterials
Volume 2014 (2014), Article ID 410717, 6 pages
http://dx.doi.org/10.1155/2014/410717
Research Article

Damp-Heat Induced Performance Degradation for InGaP/GaAs/Ge Triple-Junction Solar Cell

1Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
2Department of Electronic Engineering, College of Electrical Engineering and Computer Science, Chung Yuan Christian University, Chungli 32023, Taiwan
3Institute of Nuclear Energy Research, 1000 Wenhua Road, Jiaan Village, Longtan, Taoyuan 32546, Taiwan

Received 23 December 2013; Revised 8 January 2014; Accepted 10 January 2014; Published 24 April 2014

Academic Editor: Ting-Jen Hsueh

Copyright © 2014 Hwen-Fen Hong et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We performed accelerated tests on sealed and nonsealed InGaP/InGaAs/Ge triple-junction (TJ) solar cells in a complex high temperature and high humidity environment and investigated the electrical properties over time. The degradation of energy conversion efficiency in nonsealed cells was found to be more serious than that in sealed cells. The short-circuit current ( ), open-circuit voltage ( ), and fill factor (FF) of sealed cells changed very slightly, though the conversion efficiency decreased 3.6% over 500 h of exposure. This decrease of conversion efficiency was suggested to be due to the deterioration of silicone encapsulant. The , , and FF of nonsealed cells decreased with increasing exposure time. By EL and SEM analysis, the root causes of degradation can be attributed to the damage and cracks near the edge of cells induced by the moisture ingress. It resulted in shunt paths that lead to a deterioration of the conversion efficiency of solar cell by increasing the leakage current, as well as decreasing open-circuit voltage and fill factor of nonsealed solar cells.