LAUSR

Abstract Copper Indium Gallium Selenide (Cu(In,Ga)Se2, CIGS) absorbers were fabricated by sputtering from quaternary CIGS targets and post-selenization. Potassium (K) was doped into absorbers by potassium fluoride post deposition treatment (KF-PDT). The performances of cells and the concentration distribution of alkali elements were investigated. Recombination of CIGS cells was also detected. The introduction of K led to an increase in efficiency from 11.1% for K-free cells to 14.9% for K-doped cells, with higher open-circuit voltage (Voc). For depth profile of alkali elements in absorbers, the content of Na decreased and the content of K increased after KF-PDT. The decrease of interface recombination at CIGS/CdS interfaces is considered to be the reason for the enhanced efficiency.