A computational study of novel CsYMSe₃ (M = Cd, Zn) materials: for their potential optoelectronic and thermoelectric application

Abstract The thermoelectric performance and adjustable optical properties of chalcogenides are noteworthy. Density functional theory is employed to study the electrical, optical, and thermoelectric properties of the novel CsYMSe 3 (M = Cd, Zn) quaternary chalcogenides. A direct band gap nature was predicted based on the band profile study. Using Perdew–Burke–Ernzerhof generalized gradient approximation and TB-modified Becke–Johnson, the reported band gaps are 2.12 and 2.92 eV for CsYZnSe 3 and 2.11 and 3.07 eV for CsYCdSe 3 , respectively. The results showed that in both materials, the hybridization of the orbital Cs–p/d and the Se–p were responsible for direct energy losses. The complex dielectric function and the important linear optical parameters were investigated for possible usage in optoelectronic devices. These materials exhibit stronger absorption of photons. These materials could be employed as particularly effective UV-reflecting materials from the noticed peaks in the reflectivity spectra. Because of their negative Seebeck coefficient values, both materials show n-type conductivity across the whole temperature range. CsYZnSe 3 possesses better electrical conductivity than CsYCdSe 3 , which results in a larger ZT value.