Comparative study of structural, opto-electronic properties of Cs2TiX6-based single halide double perovskite solar cells: computational and experimental approach

This research work represents a comparative study of the structural, optical, and electronic properties of Cs2TiX6 single halide perovskite solar cell (PSC). The entire work has been carried out by experimental work under ambient conditions and followed by the DFT method. Absorbing material structural parameters (lattice constant, shape), and band gap energy can be easily estimated from the DFT approach which can be compared with the result of experimental work. Our study shows Cs2TiBr6 PSC has better band gap energy of 1.80 eV (numerically) and 1.82 eV (experimentally), open circuit voltage 0.58 V, short circuit current 2.55 mA cm(-2) for the photovoltaic application. Also, the higher Zeta potential value of Cs2TiBr6 PSC indicates that it has better material stability and is less volatile compared to Cs2TiI6, Cs2TiCl6, and Cs2TiF6 PSCs. TEM images and the SAED pattern of the active layers show a higher degree of crystallite nature of the PSCs.On the other look, investigated PSC materials Cs2TiBr6, Cs2TiI6, Cs2TiCl6, and Cs2TiF6 have shown visible light emission edges at 358 nm, 375 nm, 363 nm, 735 nm wavelength, and the optical performance area of the Cs2TiBr6, Cs2TiI6, Cs2TiCl6, Cs2TiF6 samples is recorded up to 700 nm, 760 nm, 540 nm, and 660 nm wavelength, respectively.