Integrated DFT and SCAPS-1D analysis of Tl2AgAsX6 (X = Cl, I) double perovskites for advanced energy-harvesting devices

Utilizing density functional theory (DFT), this research explores the stability, opto-electronic, photovoltaic, and thermoelectric potential of double perovskites Tl 2 AgAsX 6 (X = Cl, I) as material candidates for energy harvesting functions. Tolerance and octahedral factor analysis reveal the cubic lattice structural stability, and the formation energies are negative, confirming their dynamic stability. Mechanical properties like Pugh’s ratio, Poisson’s ratio, and Cauchy pressure indicate the consistency of ductility behavior and support the good thermomechanical performance. Other relevant electronic properties obtained from application of the TB-mBJ method show indirect band gaps of 1.692 eV for Tl 2 AgAsCl 6 and 0.882 eV for Tl 2 AgAsCl 6 . We analyze its optical properties and find high absorption coefficients in the visible range of 10 4 to 10 ⁵ order, which are ideal for photovoltaic applications. As a result, we found the maximum efficiency of 23.38% and 16.76% for the titled materials. We have characterized the thermoelectric transport properties to obtain figures of merit (ZT) for Tl 2 AgAsCl 6 and Tl 2 AgAsI 6 at 300 K, which are 0.28 and 0.40, respectively. The favorable opto-electronic and thermoelectric properties promote these materials as promising candidates for sustainable energy technologies, such as solar cells and thermoelectric devices. Layered solar cell with quantum and power conversion efficiency. • The titled compounds exhibit thermodynamic and mechanical stability. • Tl 2 AgAsCl 6 possesses more suitable electronic bandgap (1.692 eV) rather than Tl 2 AgAsI 6 (0.882 eV). • The absorption coefficients fall in the range of 10 4 –10 5 order. • The photovoltaic performance yields efficiencies of 23.38% and 16.76% for the studied materials. • The thermoelectric performance results in figures of merit of 0.28 and 0.40 at 300 K.