Extrinsic Doping of Amine-Thiol Solution-Processed Cu(In,Ga)(S,Se)2 Thin Film Photovoltaics

Na post-deposition treatments are commonly used to tackle the fine grained layers that are prevalent in solution-grown CIGS absorber layers. This work studies the effect of an evaporated NaCl layer on the electrical and morphological properties of amine-thiol solution-processed CIGS solar cells. Here, the NaCl layer acts as a post-deposition Na source and its application resulted in a CIGS device with superior JV characteristics, including a power conversion efficiency increase from 1.3% for a Na free glass substrate to 8.4 % with NaCl post deposition treatment.