First-principles investigation of Rb2Ag(Ga/In)Br-6 for thermoelectric and photovoltaic applications

Gourav and S Mukaddar and K Ramachandran and S Ghosh, INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, 122, e26910 (2022).

DOI: 10.1002/qua.26910

In this article, we have systematically investigated the structural, electronic, optical and thermoelectric properties of Rb2Ag(Ga/In)Br-6. The resulting negative formation energy along with the absence of imaginary phonon frequency confirm the thermodynamic stability of Rb2Ag(Ga/In)Br-6. In addition, the derived electronic properties by using GGA-PBE + mBJ + SOC functional show that the direct band gap values are 1.21 eV and 1.42 eV for Rb2AgGaBr6 and Rb2AgInBr6, respectively. Furthermore, the dispersed direct band nature of Rb2Ag(Ga/In)Br-6 leads to their outshining optical properties such as higher order (10(5) cm(-1)) absorption coefficient, appreciable optical conductivity, and low reflectivity. Moreover, the higher figure of merit values of Rb2Ag(Ga/In)Br-6 are resulted from their ultra-low thermal conductivity and high electrical conductivity. Thus, Rb2Ag(Ga/In)Br-6 are predicted to be potential photovoltaic and thermoelectric materials.

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