Regular Article

Optical and structure properties of CH₃NH₃PbI₃ perovskite films doped with Cesium

¹ Physics & Astronomy Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
² Physics Department, Faculty of Science, Ain Shams University, Cairo, Egypt
³ Physics Department, Faculty of Science, Taibah University, Al-Madina al Munawarah, Saudi Arabia
⁴ Physics Department, Faculty of Science (Boys Branch), Al-Azhar University, Cairo, Egypt
⁵ Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fedérale de Lausanne 1015, Lausanne, Switzerland

^* e-mail: mbm1977@yahoo.com; zein_kh@yahoo.com

Received: 26 July 2021
Received in final form: 14 September 2021
Accepted: 16 September 2021
Published online: 5 October 2021

Abstract

Methylammonium lead iodide doped with cesium (MA_1–xCs_xPbI₃, 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 MAPbI₃ 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.