Figure 2.

(a) A schematic illustration on compact layer of ZnS nanoparticles layer on Cu(In,Ga)Se₂ (CIGS) surface. (b) Current–voltage (J–V) characteristic curves of CIGS solar cells with chemical bath deposition (CBD) ZnS buffer layer and ZnS NPs buffer layer. J–V curves of ZnS NPs devices are presented in pink, red and wine red, while curves obtained from CBD ZnS devices are presented in blue, light blue and navy blue. Absorber layers of the two kinds of CIGS solar cells were separately prepared by co-evaporation. Inset shows a schematic illustration on the device structure. (c) J–V curve of Champaign CIGS solar cell with ZnS NPs buffer layer.