Screening of II-IV-V2 Materials for Photovoltaic Applications Based on Density Functional Theory Calculations

The relative stability of polymorphs and their electronic structure was investigated for II-IV-V-2 materials by using first-principles density functional theory calculations. Our calculation results show that, for Zn-, Cd-, and Be-containing compounds, nitrides favor the 2H polymorph with AB stacking sequence; however, phosphides, arsenides, and antimonides are more stable in the 3C polymorph with the ABC stacking sequence. The electronic band gap of materials was calculated by using hybrid density functional theory methods, and then materials with an ideal band gap for photovoltaic applications were chosen. The experimental synthesis of the screened materials is reported, except for CdSiSb2, which was found to be unstable in our calculation. The absorption coefficient of the screened materials, especially ZnGeAs2, was high enough to make thin-film solar cells. The higher stacking fault energy in ZnGeAs2 than the others is consistent with the larger formation energy difference between the 2H and 3C polymorphs.

Automated summary

The stability and electronic structure of II-IV-V-2 materials were investigated using first-principles density functional theory calculations, revealing preferences for specific polymorphs and ideal band gaps for photovoltaic applications. Experimental synthesis of screened materials was reported, with ZnGeAs2 showing high absorption coefficient suitable for thin-film solar cells. The higher stacking fault energy in ZnGeAs2 compared to others is consistent with its larger formation energy difference between 2H and 3C polymorphs.