A phenanthroline derivative as exciton blocking material for organic solar cells

Functionalization of phenanthroline in the 4,7-positions with pyridine groups is reported. The new material, 2,9-dimethyl-4,7-di(pyridin-4-yl)-1,10-phenanthroline (DMPP), shows lower HOMO and LUMO levels than those of bathophenanthroline (BPhen). DMPP-based zinc phthalocyanine (ZnPc):C60 flat-heterojunction solar cells exhibit a 3.5% power efficiency which is higher than that of those devices with BPhen as the exciton blocking material.