Abstract
The electronic, optical, and thermoelectric properties of Rb2TiCl6 and Rb2TiBr6 are analyzed by density functional theory (DFT). The tolerance factor and phonon dispersion are calculated to investigate the structural and dynamic stability of the cubic phase. The indirect (Gamma-X) band gaps for Rb2TiCl6 and Rb2TiBr6 are 2.85 eV and 2.12 eV, respectively. The computed optical properties reveal absorption edge in the near ultraviolet region for Rb2TiCl6 and in the visible region for Rb2TiBr6. The absorption in visible region for 496-413 nm increasing the importance of Rb2TiBr6 for optoelectronics. Thermoelectric properties computed using BoltzTraP code, for the temperature range 200-800 K which depict room temperature figure of merits (ZT) as 0.76 and 0.75 for Rb2TiCl6 and Rb2TiBr6, respectively. Therefore, the studied materials are suitable for conversion of wasted heat to electricity conversions.