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

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 (ISC), open-circuit voltage (VOC), 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 ISC, VOC, 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