Electronic transport properties of Rb2AsAuX6 (X = Cl, Br) halide double perovskites for energy harvesting applications.

The electronic structure analysis reveals semiconducting behavior, with bandgaps of 0.66 eV for Rb 2 AsAuCl 6 and 0.07 eV for Rb 2 AsAuBr 6 , attributed primarily to the interaction between As and Au states near the Fermi level. Optical investigations highlight significant absorption in the visible spectrum with onset edges in the infrared (IR) region in addition to low reflectivity (less than 10 %) and high conductivity makes both HDPs potential contender for their applications in wide range of optoelectronic devices. The thermoelectric analysis reveals promising performance, with figure of merit (ZT) values approaching ∼0.8 for Rb 2 AsAuCl 6 and ∼0.5 for Rb 2 AsAuBr 6 at room temperature. [Display omitted] • The negative Δ H f confirms the stability of Rb 2 AsAuX 6 (X = Cl, Br). • Rb 2 AsAuCl 6 /Rb 2 AsAuBr 6 have E g of 0.66/0.07 eV, correspondingly. • Both compounds have absorption in visible to infrared region. • Rb 2 AsAuCl 6 has maximum ZT value of 0.79. • Investigated compounds are suitable for TE and optoelectronic applications. Herein, we investigated the physical characteristics of two narrow band gap halide double perovskites (HDPs) Rb 2 AsAuX 6 (X = Cl, Br) by using density functional theory (DFT) calculations. Both compounds exhibit thermodynamical stability with non-magnetic ground states and stable cubic symmetry supported by geometry optimization, tolerance factor criteria, and negative formation enthalpies. The electronic structure analysis reveals semiconducting behavior, with bandgaps of 0.66 for Rb 2 AsAuCl 6 and 0.07 eV for Rb 2 AsAuBr 6 , attributed primarily to the interaction between As and Au states near the Fermi level. Optical investigations highlight significant absorption in the visible spectrum with onset edges in the infrared (IR) region in addition to low reflectivity (less than 10 %) and high conductivity makes both HDPs potential contender for optoelectronic device applications across a broad spectrum. The thermoelectric analysis reveals promising efficiency, with figure of merit (ZT) values approaching ∼0.8 for Rb 2 AsAuCl 6 and ∼0.5 for Rb 2 AsAuBr 6 at room temperature. The results indicate that Rb 2 AsAuCl 6 and Rb 2 AsAuBr 6 have the potential to be used in future optoelectronic and thermoelectric applications due to their unique combination of structural stability, tunable bandgaps, and efficient thermoelectric performance. [ABSTRACT FROM AUTHOR]