Effects of oxygen and illumination on the photovoltaic properties of organic solar cells based on phtalocyanine:fullerene bulk heterojunction

Abstract

The authors report factors that limit the photovoltaic parameters of organic solar cells based on phtalocyanine:fullerene bulk heterojunction. They show that the device photovoltaic properties and their stability are strongly influenced by O2 impurities. Oxygen affects mostly the photoelectrical properties of the fullerene and the state of the interface between phtalocyanine and fullerene domains. The illumination of the devices, especially in the wavelength range <570nm, induces photodiffusion of the oxygen into fullerene material and promotes formation of O2-fullerene dipoles and additional recombination levels due to C–O reactions that accelerate the device degradation.