FIRST PRINCIPLE DFT CALCULATION OF MAPbX3 (X=Cl, Br, I) PEROVSKITES

Abstract

Recent improvements in quantum mechanical theory algorithms has enabled more precise quantum mechanical calculations of advanced materials. Due to these algorithmic improvements more accurate theoretical modelling is now possible from which one can calculate and study material properties that were very challenging before. In last few years, Methyl Ammonium Lead Halide (MAPbX3) has attracted more attention because of its high efficiency in solar cells. Here in this research work, first principle DFT calculation is performed to study optimized crystal structure, electronic and elastic properties of the Methyl Ammonium Lead Halide perovskites using two different exchange-correlation functional namely local density functional and generalised gradient exchange correlational functional. The properties calculated from this study is closely in agreement with the literature and experimental data. This study successfully calculated the optimized crystal structures, electronic structures, E-V plot for the MAPbX3 (X=Cl, Br, I) perovskites. In the very first chapter of this dissertation, very basic information about perovskite materials and first principle calculation is represented. The importance of first principle DFT over other methods is explained. In the next chapter, the literature review is done. It included the literature and articles related to the application and evolution of solar energy as a renewable energy alternative. Further, evolution of density functional theory (DFT) and its backbone in the form of theorems, are briefly introduced with the help of research papers. After that various first principle DFT study on Methyl Ammonium Lead Halide perovskites reported since few years, are represented with the help of research papers summary. The third chapter of this dissertation work gives detailed summary of the density functional theory background, its evolution, approximation used and some important equations and methods used during the DFT calculation. Thus it sets theoretical background for first principle DFT calculation. In the fourth chapter, computational details of first principle DFT like DFT package code used for the calculation, computational parameter calculations are described. The fifth chapter gives details about the synthesis of perovskite material film. It also tells about the characterization techniques used for the study of synthesized perovskite films. To calculate energy band gap value of perovskite films, UV-vis spectroscopy is done and Tauc plot is drawn for the band gap values. For the confirmation of successful perovskite film synthesis, XRD analysis is done which confirms the formation of the perovskite films without any other impurity. To analyse the topographic details of crystals formed and arrangement of overall crystals, FE-SEM image is taken. In sixth chapter of this study, plot of calculated electronic structures with density of states plot, optimized structures are attached. A comparative study between experimental and calculated parameters is done in this section. In the next chapter possible reasons (explanations) for the acquired results with concluding remarks are given. Final chapter makes the reference section of this dissertation.