First principles studies of CsLnCdTe3 (Ln = Gd−Tm) for green energy resources

Abstract

The structural, electronic, optical and thermoelectric properties of alkali metal cadmium telluride CsLnCdTe3 (Ln = Gd–Tm) semiconductors are investigated using density functional theory. The structural parameters are calculated using generalized gradient approximation which show a close agreement with experimental values. The electronic properties are investigated using GGA + U approximation because the Hubbard potential (U) gives better results and are very reliable for band structure calculations. The predicted band gaps show direct band gap nature. The estimated band gap of CsTmCdTe3 is 1.93 eV which is in agreement with the experimental value of 2.01 eV. The narrow band gaps, high dielectric constants and high absorption ranges make these materials suitable hosts for solar energy conversion applications. BoltzTrap calculations are used to obtain thermoelectric parameters like seebeck coefficient, electronic and thermal conductivity. The high seebeck effect and large power factor values confirm the efficiency of these materials in thermoelectric converter technology.