The effects of exciton-diffusion blocking layers on pentacene/C60 bulk heterojunction solar cells

Organic thin film solar cells, with structures based on pentacene/C60 bulk heterojunctions, have been fabricated and characterized. The effect of introducing an exciton-diffusion blocking layer (EBL) of 3,4,9,10-perylenetetracarboxylic dianhydride, between the active layer and the metal layer in the solar cell, was investigated. It was shown that optimized structures containing EBLs resulted in an improvement in solar cell conversion efficiencies. The energy levels of the molecules were calculated and are subsequently discussed.