SEM images. (a) The surface of a CIGS layer, (b) the surface of a CIGS/P3HT:PCBM bilayer, and (c) the cross-section of the CIGS/P3HT:PCBM bilayer. The CIGS layers were deposited at a substrate temperature of 400°C for 3 min.
Zhao et al. Nanoscale Research Letters 2014 9:308 doi:10.1186/1556-276X-9-308