Strain Effect on Optoelectronic and Thermoelectric Properties of the Perovskite NaGeI₃

Abstract

In this research, we investigate the impact of strain on the optoelectronic and thermoelectric properties of the NaGeI 3 perovskite by employing a combination of density functional theory (DFT) and Boltzmann transport theory. Initially, we examine the NaGeI 3 material’s structural, electronic, and optical properties using the generalized gradient approximation (GGA). The results reveal that this material proves the behavior of a semiconductor with a p-type character and possesses interesting optical properties. Furthermore, we outline the thermoelectric properties of the material, including the Seebeck coefficient, the electrical and thermal conductivities, the figure of merit (ZT), and the power factor (PF). Our investigations indicate that the Seebeck coefficient exhibits positive and increasing values with the application of strain. This confirms the p-type semiconductor behavior observed in the studied material. Additionally, the NaGeI 3 compound demonstrates significantly high values of the ZT when compared with the existing thermoelectric materials, both at room and high-temperature values. This suggests that the NaGeI 3 compound stands as a promising potential candidate for optoelectronic and/or thermoelectric applications.