Fig. 5: Defect analysis for Voc improvement.

a Defect density derived from the capacitance-voltage (C-V) and the drive level capacitance profiling (DLCP) measurements for samples CISe, FG-0, B1, C, and C-RbF. b The variation of VOC, Eg and VOC,def for the corresponding CIGSe solar cells. c Summary graph of VOC with different Eg for typical CIGSe solar cells. The device in this work is marked with a blue star.