Copper-phthalocyanine-based organic solar cells with high open-circuit voltage

We report on a copper phthalocyanine (CuPc)/3,4,9,10 perylenetetracarboxylic bisbenzimidazole (PTCBI) organic solar cell with an aluminum cathode exhibiting an open-circuit voltage (VOC) of 1150 mV and a short-circuit current density (JSC) of 0.125mA∕cm2. For comparison, aluminum and silver were used as electrode materials and their effects on device characteristics were studied; silver yielded lower VOC but higher JSC and higher efficiency. Results could be understood through a model that hypothesized surface modification of CuPc by PTCBI and the formation of a thin insulating layer between aluminum and PTCBI when aluminum was used as electrode.