MAPbI2.9-xBrxCl0.1 hybrid halide perovskites: Shedding light on the effect of chloride and bromide ions on structural and photoluminescence properties

The optical and structural properties of CH3NH3PbI3 can be adjusted by introducing other extrinsic ions such as chloride and bromide. In this work, mixed bromide iodide lead perovskites with a 10% fraction of chloride were prepared from methylamine, lead nitrate and the corresponding hydro acid (X = I, Br, CI). The effect of bromide and chloride incorporation on different properties of perovskite thin film was investigated. The Pawley fit method indicates the formation of the iodide halide MAPbI3 Pm -3 m cubic phase for x=0 and the tetragonal P4/mmm phase for x >= 0.3. All deposited films showed a strong absorbance in the UV-vis range. The band gap values were estimated from absorbance measurements. It was found that the onset of the absorption edge for MAPbI(2.9-x)Br(x)Cl(0.1) thin film perovskites ranges between 1.60 and 1.80 eV. Moreover, it was found that both CI and Br affect the PL emission of the mixed halide lead perovskite, the MAPbI(2.9-x)Br(x)Cl(0.1) films displayed intermediate values from 730 nm (MAPbI(22)Br(0.7)Cl(0.1)) to 770 nm (MAPbI(2.6)Br(0.3)Cl(0.1)). 2016 Elsevier B.V. All rights reserved.