Preparation and characterization of photoelectrical conversion properties of organic solar cells based on P3HT:PCBM composite materials

Abstract

Organic solar cells (OSC) based on P3HT:PCBM photoactive composite materials with a multilayer structure of ITO/ZnO/P3HT:PCBM/LiF/Al were prepared in this study. The P3HT:PCBM composite thin films with 2/3, 1/1 and 3/2 ratios of P3HT/PCBM were prepared by spin-coating. The nano ZnO buffer layer was deposited by Rf-sputtering, and the shallow contact of LiF/Al was made by vacuum evaporation. Measurements of current-voltage characteristics of the devices under illumination of solar radiation with a density of 50 mW/cm2 showed that for the best photoactive composite (namely 1/1 of P3HT/PCPM ratio) the open-voltage reached a value as high as 0.36 V, the shot-circuit current - 5.80 mA/cm2 and the fill factor - 0.54; consequently, the photoelectrical conversion efficiency was found to be 2.25%. This suggests a potential application of the large-area OSCs in utilization of solar energy.