Achievement of 17.5% efficiency with 30 × 30cm2-sized Cu(In,Ga)(Se,S)2 submodules

The efficiency of 17.8% on a 30 × 30cm
²
-sized Cu(In,Ga)(Se,S)
₂
(CIS)-based thin-film submodule was achieved. The device structure is same as our previous works; monolithically integrated CIS-based cells on a Mo-deposited glass substrate with a Zn(O, S, OH)
_x
buffer and a ZnO window. Current Progress was mainly brought by review of the band profile of the absorber layer. More specifically, fine tuning of the grading of Ga/(Ga+In) and S/(Se+S) ratio turned out to improve the value of V
_oc
× J
_sc
by a factor of as much as three percent.