Structural, opto-electronic, and elastic responses of double perovskite K₂NaTiA₆ (A=Cl and Br) for photovoltaic application: A DFT study

The physical properties of double halide perovskite K 2 NaTiA 6 ([Formula: see text] and Br) were investigated using the first principles study root using the Wien2k package for renewable energy generation and solar cell applications. Research on halides is expanding in the field of optoelectronics and is believed to meet the requirements for addressing energy shortages. Moreover, Pugh and Poisson’s ratios indicate their elastic properties. The electronic properties and calculated the bandgaps using modified Becke–Johnson (mBJ) potentials, resulting in bandgaps of 1.09[Formula: see text]eV and 1.36[Formula: see text]eV for K 2 NaTiCl 6 and K 2 NaTiBr 6 , respectively. The optical properties were evaluated using complex dielectric functions, and the results showed optimal light absorption in the infrared (IR) region. These findings suggest their potential for optoelectronic, device applications and are expected to support future experimental research on the suitability of K 2 NaTiX 6 ([Formula: see text] and Br) for optical devices.