Theoretical Photovoltaic Conversion Efficiencies of ZnSnP₂, CdSnP₂, and Zn1-xCdxSnP₂Alloys

The performances of ZnSnP 2 , CdSnP 2 , and Zn 1- x Cd x SnP 2 alloys as solar cell photoabsorbers are assessed using photovoltaic conversion efficiency simulations in conjunction with first-principles calculations based on hybrid density functional theory. The band gap of Zn 1- x Cd x SnP 2 decreases with increasing Cd content x and shows a small bowing. The electronic structure and optical absorption spectrum depend weakly on the composition, aside from the band gap and spectral threshold. The conversion efficiency is almost converged to the Shockley–Queisser limit at a photoabsorber thickness of a few micrometers for any composition of Zn 1- x Cd x SnP 2 , similarly to the cases of GaAs, CdTe, CuInSe 2 , and CuGaSe 2 .