Numerical Study of Chalcopyrite (MgSnP2) and Perovskite (SrTiO3) Compounds for Photovoltaic Applications

This paper presents a systematic investigation of the structural, elastic, electronic, and optical properties of two semiconductor materials: the tetragonal chalcopyrite, MgSnP2 and the cubic perovskite SrTiO3. These materials were chosen for their distinct characteristics, including optimal band gaps conducive to photovoltaic (PV) conversion and strong absorption, particularly within the visible solar spectrum. Structural optimization and property calculations were performed using the CASTEP (CAmbridge Serial Total Energy Package) code within Density Functional Theory (DFT), utilizing the Generalized Gradient Approximation (GGA) with the Perdew–Burke–Erzenhof (PBE) exchange-correlation function. The calculated lattice parameters align excellently with previously reported theoretical values. Analysis of the electronic band structure provides compelling evidence of semiconductor behavior in the compounds. Electronic properties reveal band gaps of Eg = 1.255 eV for MgSnP2 and Eg = 1.83 eV for SrTiO3, respectively, from G-G and R-G high symmetry points, enabling them to absorb a wide range of the solar spectrum. The obtained B/G ratio for MgSnP2 is 2.6, surpassing the critical value of 1.75 according to Pugh’s criterion, indicating its ductile or malleable nature with significant deformation capacity before failure. Conversely, the B/G ratio for MgSnP2 is 1.49, below the threshold of 1.75, classifying it as a brittle material with limited plastic deformation and a tendency for sudden fracture. Finally, the calculated solar cell efficiency of MgSnP2 is found to be 25.5%, comparable to conventional silicon-based cells, while SrTiO3 exhibits an efficiency of 20.6%, making it a promising candidate for use as a transparent conductive oxide (TCO) or buffer layer in PV devices. These results highlight the potential of both materials in advancing next-generation PV technologies.