An ab-initio study of ternary oxide phases of MgSnO₃ as an application in solar cells

MgSnO₃ in Ilmenite, Perovskite and LiNbO₃ type crystal structures have been studied by first-principles methods using density functional theory (DFT) and beyond. We found that MgSnO₃ in LiNbO₃ type is both mechanically and dynamically stable, whereas Ilmenite and Perovskite crystal structures are mechanically stable but dynamically unstable. Vibrational stability in MgSnO₃ requires some distortion in octahedra caused due to the bonding strength between the atom pairs Sn-O in LiNbO₃ type crystal structure. Similarly, Ilmenite and Perovskite crystal structures need a higher number of Mg-Sn and (Mg-Mg, Sn-Sn, O-O and Mg-O) bonds respectively for stability. Ilmenite and LiNbO₃ type crystal structures can be deployed as window layers showing a large bandgap of 5.22 eV and 3.88 eV respectively, together with a lower absorption coefficient and reflectivity. Likewise, Perovskite crystal structure with a bandgap of 2.55 eV can be utilized as an absorber layer that absorbs green light of solar irradiation in tandem solar cells. Perovskite crystal structure has the lowest charge carrier effective masses among all the structures in MgSnO₃. LiNbO₃ type crystal structure has a high hardness of 56.5 GPa. It should be assessed experimentally in applications requiring super-hard materials.