Indium sulfide-based electron-selective contact and dopant-free heterojunction silicon solar cells

Abstract

Dopant-free carrier-selective contacts have gained attention for application in silicon solar cells because of their simpler preparation process and low-temperature fabrication. However, there were few reports on efficient p-Si solar cells having dopant-free electron contacts. In this study, indium sulfide (In2S3) thin films were successfully deposited by simple thermal evaporation at room temperature and used as dopant-free electron-selective contacts on the front side of p-Si heterojunction solar cells. The changes in crystal structures, optical properties, compositions, and energy-band structures of the In2S3 thin films due to different annealing temperatures were investigated. The champion conversion efficiency of 10.72% was achieved with lightly doped, textured front Czochralski (Cz) p-Si wafers, and a low thermal energy cost. This study demonstrates that In2S3 film is an effective electron-selective contact for silicon solar cells, providing an alternative simple process to the fabrication of dopant-free optoelectronic devices.