Theoretical engineering of physical characteristics of novel double perovskite Cs2CeAgX6 (X= Cl, Br) for optoelectronic and thermoelectric applications

The present study unveils physical characteristics, including elastic parameters, phonon dispersion, electronics, optical, and thermoelectrics behavior’s novel double perovskite Cs2CeAgX6(X= Cl, Br) by performing FP-LAPW computational approach. The mechanical stability of studied compounds has been addressed rigorously, and both compounds are ductile, revealing their potential for the fabrication of optoelectronic and thermal devices. Moreover, the phonon dispersion advocated about dynamical stability of the Cs2CeAgX6(X= Cl, Br) compounds. Both studied compounds have shown a wider band gap, a clear signature of a semiconductor nature. Spin-polarized electronic band structure's outcomes as well as electronic density of states have been computed using TB-mBJ approximation. Moreover, Cs2CeAgBr6 offers a reduced gap rather then Cs2CeAgCl6. The photo response analysis shows that Cs2CeAgBr6 can absorb various ultraviolet (UV) and visible electromagnetic radiations. Henceforth, Cs2CeAgBr6 is found to be a more suitable aspirant for optoelectronic device fabrication. Regarding composites' thermoelectric behaviour, the Seebeck coefficient reflects that studied materials are hole-based semiconductors computed by the BoltzTrap code. Cs2CeAgCl6 has shown a higher thermal conductivity magnitude than Cs2CeAgBr6, so It's a potential thermoelectric material devices and allied applications.