Characterization of Direct Light Soaking Effect on Transparent Passivating Contact Solar Cells

Abstract

The optimization of a transparent, passivating, and conductive contact approach for the front side of silicon heterojunction solar cells has been widely studied due to the observed parasitic absorption losses in the amorphous silicon layers and the passivation losses during Indium Tin Oxide sputtering. To enable high efficiency crystalline silicon solar cells based on the combined front transparent passivating contact surface and rear silicon heterojunction structure, the present study focuses on curing the sputter damage by the application of light soa king without pre annealing treatment. The investigation of different light soaking conditions defines the heat assisted light soaking performed at 175 during 360s as a suitable operating condition to characterize the process on transparent passivating co ntact solar cells. The combination of heat and light during the curing process was found to be an inseparable effect in order to achieve better performance. A significant reduction in the open circuit voltage loss is observed after direct light soaking cur ing, resulting in a passivation recovery. The measurement of the photovoltaic parameters shows an interesting overall power conversion efficiency of 23.4% achieved for a n open circuit voltage of 736 mV, a fill factor of 80%, a short circuit current density of 39.75 mA/cm 2 and 1.146 Ω cm 2 as a contribution of series resistance. The study demonstrates the potential of direct light soaking to improve the transparent passivating and conductive contact solar c ells and contributes to a better understanding of the internal mechanisms involved.