7.3% efficient CuInSe2 solar cell

A 7.3%, 3.3 cm² active area efficient ZnO/thin CdS/CuInS₂ solar cell is demonstrated with 22.7 mA/cm² J_sc, 592 mV V_oc, and 0.546 fill factor. X-ray diffraction shows that the CuInS₂ films with are predominantly randomly oriented chalcopyrite CuInS₂ with additional minor phases such as In₂S₃ and Cu_2-xS present. Optical transmission and reflection data for CuInS₂ films on glass are also shown. Optical transmission implies a 1.4-eV bandgap, less than the 1.55-eV bandgap for single-crystal CuInS₂, but consistent with other reported thin-film results. It is concluded that the resolution of several materials, device, and fabrication issues will result in efficiencies of greater than 15%.