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

The physical properties of double halide perovskite K2NaTiA6 (A=Cl 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 1.09eV and 1.36eV for K2NaTiCl6 and K2NaTiBr6, 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 K2NaTiX6 (X=Cl and Br) for optical devices.