Photovoltaic properties of cadmium sulfide/trivalent-metal phthalocyanine heterojunction devices

Thin-film photovoltaic devices consisting of a CdS/trivalent-metal phthalocyanine heterojunction have been prepared. The devices are fabricated by first electrodepositing a thin film of CdS onto a transparent conducting indium-tin-oxide substrate and then depositing phthalocyanine and gold layers sequentially in a vacuum coater. The trivalent-metal phthalocyanines used are chloroaluminium chlorophthalocyanine (ClAlClPc), chloroaluminium phthalocyanine (ClAlPc), and chloroindium phthalocyanine (ClInPc). Under an AM2 illumination of 75 mW cm−2, these heterojunction devices produce an open-circuit voltage Voc of 0.70 V and short-circuit current Jsc of 0.8 mA cm−2. The conversion efficiency is about 0.2%, which represents one of the highest values reported for phthalocyanine photovoltaic devices at high light intensity.