Promising photovoltaic, optoelectronic and p-type thermoelectric Sr4Pn2O (Pn = Sb, Bi) compounds: A first principles study

Tetra-strontium di-pnictide oxides Sr4Pn2O (Pn = Sb, Bi) belong to the oxypnictide-type materials attracting a lot of attention due their unique properties which are very advantageous for photovoltaic and thermoelectric applications. In spite of the fact that structural features of Sr4Pn2O (Pn = Sb, Bi) are known, however, their ability for applying in renewable energy has not been discovered yet. Therefore, in this study, the electronic structure of the two compounds was studied in detail that provides a key knowledge on understanding their optical and thermoelectric properties. The present data indicate that Sr4Pn2O (Pn = Sb, Bi) oxides have suitable band structure for photovoltaic applications with high absorption rates of 105-106 cm-1. The two compounds are also promising p-type thermoelectric materials with the figure of merit of about 0.45-0.55. Sr4Pn2O materials have strong nonlinear characteristics, making them highly promising for optical switching devices. Our research provides further insights into the features of Sr4Sb2O and Sr4Bi2O compounds besides current experimental data, demonstrating that both compounds have promising characteristics as optoelectronic materials.