Study of optoelectronic and thermoelectric properties of double perovskites Rb2AgBiX6 (X = Br, I): by DFT approach
Department of Physics, College of Science, Jouf University, P.O. Box 2014, Al-Jouf, Sakaka, Saudi Arabia
2 Physics Department, Faculty of Science, Assiut University, 71516, Assiut, Egypt
3 Palestinian Ministry of Education and Higher Education, Nablus, Palestine
4 Department of Physics, Government Post-Graduate Jahanzeb College Saidu Sharif, Swat 19130, Khyber, Pakhtunkhwa, Pakistan
Accepted: 22 August 2022
Published online: 31 August 2022
From the last few decades, double perovskites are becoming the merging materials for solar cells and renewable energy applications. Here in this article, we have explored the electronic, optical, and thermoelectric characteristics of Rb2AgBiX6 (X = Br, I) by using modified Becke and Johnson potential through density functional theory approach. The band gaps of 1.88 eV and 1.22 eV are computed for Rb2AgBiBr6 and Rb2AgBiI6, respectively. The reduction in band gap occurs by the replacement of Br with I due to hybridization of cations and anions sub-states. The optical properties are addressed by absorption coefficient, refractive index, polarization of light, reflection, and energy loss factor. The absorption bands fall in ultraviolet region for Rb2AgBiBr6, and in visible region for Rb2AgBiI6 which increases their potential for optoelectronics. The thermoelectric characteristics are addressed by figure of merit (ZT) scale. The ultralow thermal conductivity and large Seebeck coefficient increase their ZT to make them significant for thermoelectric generators.
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