Effect of halide-mixing on tolerance factor and charge-carrier dynamics in (CH3NH3PbBr3-xClx) perovskites powders

This work demonstrates a route to making mixed halide perovskite powders at room temperature by the anti-solvent-assisted crystallization method. Although, mixed halide CH(3)NH(3)PbBr(3-x)Cl(x)perovskites have been prepared by different methods, however,to the best of our knowledge the anti-solvent-assisted crystallization method is employed here for the first time to prepare mixed halide CH(3)NH(3)PbBr(3-x)Cl(x)perovskite powders. Solution-processed methyl ammonium lead tribromide CH3NH3PbBr3(x = 0) and different amounts of chloride (Cl) containing mixed halide perovskites (CH3NH3PbBr3-xClx) were prepared for compositions ofx = 0.5, 1, 1.25, 1.75. It reveals that bulk CH(3)NH(3)PbBr(3-x)Cl(x)samples are highly crystalline and exists in pure single cubic phase with an increased tolerance factor as compared to pure CH3NH3PbBr3. The CH(3)NH(3)PbBr(3)perovskite has space-groupPm-3 mand a cell parameter of 5.930 angstrom (volume = 206 angstrom). The synthesis route adopted here gives access to hybrid perovskites powders with high Cl content and hence enables the band gap to be precisely tuned over a range from 2.26 to 2.49 eV. The powder samples display the subtle shifts in the emission spectra and the photoluminescence kinetics exhibits a decrease in average lifetime by increasing the Cl contents due to the presence of trap states in the structures that encourage non-radiative recombination of charge carrier. Conventionally, the CH3NH3PbBr3-based inverted solar cell architecture is prepared via mixing of the CH3NH3Br and PbBr(2)precursors. In contrast, herein, the precursor solutions are directly prepared from the CH(3)NH(3)PbBr(3)powder and the active layer of the inverted perovskite solar cells are then spin coated using this solution. The highV(oc)value of the fabricated solar cells potentially makes it a promising candidate for tandem photovoltaic, photocatalytic water splitting, and semi-transparent photovoltaic applications.