High-performance photocatalytic and thermoelectric properties of CsTlCl3 and CsTlBr3 halide-perovskites for water splitting and energy conversion applications

This study presents the investigation of the structural, electronic, optoelectronic, Photocatalytic, thermodynamic and thermoelectric properties of CsTlX 3 (X = Cl, Br) halide perovskites using first principles Density Function Theory with the method of Full- Potential Linearized Augmented Plane Wave (FP-LAPW). The structural optimization indicates that the cubic phase is energetically favorable. Electronic band structure analysis show direct semiconducting band gaps of approximately 1.70 eV and 0.86 eV for CsTlCl 3 and CsTlBr 3, conforming their suitability for optoelectronic and photocatalytic applications. Using Boltzmann transport theory with in constant relaxation time approximation we calculated thermoelectric properties. These properties give significant seebeck coefficient, favorable electrical conductivity and low thermal conductivity. These properties suggest promising thermoelectric performance. At room temperature the ZT value is investigated 1 for both materials. Thermodynamic investigation based on the quasi-harmonic Debye model demonstrates good thermal stability, characterized by increasing entropy, thermal expansion and heat capacities and decreasing Gibbs free energy with temperature. The obtained results proved that CsTlCl 3 and CsTlBr 3 are promising materials for future thermoelectric and energy-conversion technologies.