Review on Alkali Element Doping in Cu(In,Ga)Se 2 Thin Films and Solar Cells

• DOI: 10.1016/j.eng.2017.04.020
• Publication Date: 2017-10-17T04:45:33Z
• Authors: Yun Sun; Shuping Lin; Wei Li; Shiqing Cheng; Yunxiang Zhang; Yiming Liu; Wei Liu
• Keywords: Passivation; Homojunction; Open-circuit voltage; Acceptor

This paper reviews the development history of alkali element doping on Cu(In,Ga)Se2 (CIGS) solar cells and summarizes important achievements that have been made in this field. The influences incorporation strategies CIGS absorbers device performances are also reviewed. By analyzing surface structure electronic property variation induced by fluoride (NaF KF) post-deposition treatment (PDT), we discuss interpret following issues: ① delamination thin films Na facilitates CuInSe2 formation inhibits Ga during low-temperature co-evaporation processes. ② mechanisms carrier density increase due to defect passivation at grain boundaries surface. ③ A thinner buffer layer improves short-circuit current without open-circuit voltage loss. is attributed not only better coverage early stage chemical bath deposition process, but higher donor (CdCu+) density, which transferred from acceptor (VCu−) strengthens buried homojunction. ④ KF-PDT-induced lower valence band maximum absorber reduces recombination absorber/buffer interface, fill factor cells.