Optical and structure properties of CH3NH3PbI3 perovskite films doped with Cesium

Methylammonium lead iodide doped with cesium (MA(1-x)Cs(x)PbI(3), x = 0, 0.03, 0.05, 0.1) thin films were prepared with and without chlorobenzene (CB). X-ray diffraction analysis applying the Rietveld refinement method is carried out, and the effect of Cs and CB on the lattice parameters, crystallite size, lattice microstrain, and dislocation density of the formed films is examined. SEM images with different magnifications are used to investigate the films' morphology and homogeneity. Adding CB reduced the number of pinholes and the grain size in the formed films. The UV-Vis-NIR spectroscopy technique was used to investigate the transmittance, reflectance, and absorbance spectra for Cs doped MAPbI(3) with and without CB. In general, for Cs doped films, adding CB increases the film transmittance. The refractive index of 3% Cs doped film has the highest value among the films without CB. The optical bandgap, refractive index, and optical conductivity for films with CB are higher than those without CB for all doping Cs values. The influence of Cs doping and CB addition on the photoluminescence (PL) emitted spectra was studied using a PL set-up with a laser source of 532 nm.