ILGAR In2S3 buffer layers for Cd-free Cu(In,Ga)(S,Se)2 solar cells with certified efficiencies above 16%

In2S3 buffer layers have been prepared using the spray ion layer gas reaction deposition technique for chalcopyrite-based thin-film solar cells. These buffers deposited on commercially available Cu(In,Ga)(S,Se)2 absorbers have resulted in solar cells with certified record efficiencies of 16.1%, clearly higher than the corresponding CdS-buffered references. The deposition process has been optimized, and the resulting cells have been studied using current–voltage and quantum efficiency analysis and compared with previous record cells, cells with a thermally evaporated In2S3 buffer layer and CdS references