Thermal Annealing Recovery and Saturation of Light-Induced Degradation of Amorphous Silicon Alloy Solar Cells with Different Microvoid Density

Abstract

We have studied the light-induced degradation and thermal annealing recovery of amorphous silicon alloy solar cells with different microvoid density in the intrinsic layer. The microvoid density was changed by altering the deposition rate. The experiments show that cells with higher microvoid density need longer annealing time to recover after prolonged light-soaking. As a consequence, cells with high density of microvoids do not seem to saturate even after long duration of light exposure. The cells with high microvoid density also show much lower degraded efficiency. A careful comparison between degradations caused by accelerated and one-sun light soaking and subsequent annealing recovery indicates that the defects created in the two cases have different nature.