Revealing the improved elasto-mechanical, opto-electronic, thermodynamic and thermoelectric properties of double perovskites Rb2TlAF6(A = Ir, Rh): A DFT analysis
Bakar A. Ahmed M. Omarova Z.B. Toleubay G.K. Shalenov E.O.
15 August 2025Elsevier B.V.
Surfaces and Interfaces
2025#71
The current study focuses on the structural, mechanical and optoelectronic properties of fluorine based double perovskites Rb2TlAF6(X = Ir, Rh) utilizing first principles calculations using Wien2k code. The optimized structural parameters are first explored and the optimized lattice constant for Rb2TlIrF6 (Rb2TlRhF6) is 9.35 Å (9.26 Å). The formation energy of both materials confirms their structural stability. The bulk modulus for Rb2TlIrF6 and Rb2TlRhF6 is 53.92 and 52.54 GPa. Both materials show ductile behavior assessed by their Poisson ratio, Pugh ratio, and Cauchy pressure. The accurate band gap energy is investigated using Generalized Gradient Approximation of Perdew–Burke–Ernzerhof (PBE-GGA) and the correction is reported using Tran-Blaha modified Becke Johnson modified (TB-mBJ) functional. The band gap of Rb2TlIrF6 with TB-mBJ is 3.79 (indirect) and Rb2TlRhF6 is 3.55 eV (direct). Further, the electronic band structures are corrected under the effect of spin orbit coupling. The complex dielectric function, complex refractive index along with reflection and absorption are investigated to explore the optical activity of these materials. Both materials show significant absorption and low reflection indicating their potential utilization in solar technology and optoelectronic applications because large absorption will convert more light into useful energy. The thermodynamic parameters like heat capacities CV, CP, entropy (S), thermal expansion coefficient (α), Debye temperature (ΘD), Grüneisen parameter (γ), volume and Bulk modulus have also been investigated against a range of pressure and temperature. Thermoelectric investigations are also performed to test the utility of these materials for energy applications.
Band gap , Double perovskites , Optical properties , Optimized parameters , Thermodynamic
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Department of Materials Engineering, School of Materials Science and Engineering, Zhejiang Sci-Tech University, Hangzhou, 310018, China
of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan
Department of Standardization, Certification and Metrology, Satbayev University, Almaty, 050013, Kazakhstan
Department of Materials Science, Nanotechnology and Engineering Physics, Satbayev University, Almaty, 050013, Kazakhstan
Department of General Physics, Satbayev University, Almaty, 050013, Kazakhstan
Department of Materials Engineering
of Natural Science and Technology
Department of Standardization
Department of Materials Science
Department of General Physics
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