Solution Processed Bathocuproine for Organic Solar Cells

PTB7/PC₇₁BM bulk heterojunction solar cell devices where the conventional calcium hole-blocking layer has been replaced by a solution processed bathocuproine (BCP) layer is described. The BCP thin film was deposited via spin coating from a dilute solution of BCP in a mixture of toluene and methanol directly on the top of the active layer. The silver cathode was subsequently deposited via thermal evaporation. The study shows that solar cells devices comprising solution-processed BCP show similar performance than devices made from either calcium or evaporated BCP. Moreover, the devices made from solution-processed BCP show superior stability in air than calcium and evaporated BCP-based devices. This is to the best of our knowledge, the first report of the use of solution processed BCP in organic solar cells.