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 solutiongrown 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.