Kazunori Kawamura

Multi layer precursor method for Cu(In,Ga)Se2 solar cells fabricated on flexible substrates

Cu(In,Ga)Se2 (CIGS) solar cells are deemed one of the highest conversion efficiency thin-film solar cells, and the utilization of flexible (stainless steel; SUS) substrates offers several advantages in terms of lowering manufacturing costs. In this work, CIGS films on SUS substrates are deposited by the so-called “multi layer precursor method” using multi layer co-evaporation of material sources. The examination concentrates on the influence of growth temperature and Ga/III, Ga/(In + Ga), profiles of CIGS layers on the cell performance. According to the results, CIGS crystallization is primarily manipulated by growth temperature. Ultimately, the deposition of CIGS on a flexible SUS substrate can be readily controlled to obtain a suitable double Ga/III-grading profile with large grains of CIGS for a high cell efficiency of 16.05%.