Tailoring the optoelectronic and transport properties of Cs[formula omitted]AgSb(Cl,Br)[formula omitted] halide double perovskites for thermoelectric and optoelectronic applications

Abstract

Double halide perovskites containing halides have garnered considerable attention as efficient semiconductors suitable for thermoelectric and optoelectronic applications due to their outstanding environmental stability, efficiency, and non-toxic nature. In our investigation, we thoroughly examined the structural, electronic, optical, and thermoelectric properties of halide double perovskites Cs2AgSb(Cl,Br)6 using density functional theory. Applying Born stability and tolerance factor criteria, we confirmed the structural stability of Cs2AgSb(Cl,Br)6. Additionally, we conducted a comprehensive assessment of their electronic, optoelectronic, and thermoelectric properties. The band structure analysis revealed that Cs2AgSbBr6 and Cs2AgSbCl6 possess semiconducting indirect band gaps of 1.64 eV and 2.44 eV, respectively. Furthermore, an investigation of the optical properties based on the complex dielectric function demonstrated that both compounds exhibit low reflectivity, not exceeding 15%, and very high absorption coefficients in the order of 105 cm−1 in the visible and UV regions. Moreover, the thermoelectric properties were investigated using the BoltzTraP simulation package. The findings unveiled a strong Seebeck coefficient and noteworthy electrical conductivity. These results highlight the adaptability of these materials, indicating their potential for diverse applications, including thermoelectric and optoelectronic devices.