Zn3P2 and Cu2O substrates for solar energy conversion

摘要

Zinc phosphide (ZnP) and cuprous oxide (CuO) are promising and earth-abundant alternatives to traditional thin film photovoltaics materials such as CIGS, CdTe, and a-Si. We have prepared high purity substrates of ZnP from elemental zinc and phosphorus, and CuO by the thermal oxidation of copper foils, to investigate their fundamental material properties and potential for solar energy conversion. Photoluminescence-based measurements of ZnP substrates have revealed a fundamental indirect band gap at 1.38 eV and a direct band gap at 1.50 eV, with time-resolved data indicating minority carrier diusion lengths of ≥7 μm. Solar cells based on Mg/ZnP junctions with solar energy conversion efficiency reaching 4.5% were examined by composition profiling to elucidate the passivation reaction between Mg metal and ZnP surfaces. Semiconductor/liquid junctions incorporating CuO substrates exhibited open-circuit voltage, V, values in excess of 800 mV and internal quantum yields approaching 100% in the 400–500 nm spectral range.