Interaction of organic semiconductor with low work function metals Ca and K

Interaction of bathocuproine (BCP) with low work function metals Ca and K was studied by density functional theory. New peaks known as interface states were observed near the Fermi level in BCP molecular gap due to interaction of metal (s) levels with BCP LUMO mainly composed of C (2p). It was analyzed that the charge injection becomes better at the interface between BCP and low work function electrodes. These findings indicate that the improvement in electrical characteristics is due to the improvement in charge injection with low work function metal electrodes. The effects of low work function on electrical properties were discussed.