Theoretical Study of the Electronic and Optical Properties of Polypyrrole (PPy) Polymer Nanoparticles Doped with TiO2 and ZnO

Designing suitable nanoparticles of polymer Polypyrrole (PPy) backbones to improve doping efficiency can provide a new direction in enhancing electronic and optical properties by enhancing the efficiency of doping (ZnO) and (TiO2). Objective: In this study geometry optimization in the gas phase, UV-visible, IR spectrum, and several electronic characteristics have been studied. All computations were based on density functional theory (DFT). Results showed the analysis of ultraviolet and visible spectra. A peak appears in the visible region, and this corresponds to transitions between electronic energy levels within the conjugated polymer chain. This peak is due to π-π* transitions, and these transitions are sensitive to doping levels and oxidation states. The results show the spectroscopic analysis highlights the interactions between TiO2 and PPy nanoparticles. TiO2 particles are characterized by energy gaps that define the absorption edge of the electromagnetic spectrum and thus affect the absorption spectrum of the material as a whole. These effects lead to changes in the locations of the absorption peaks, and this explains changes in the electronic structure and optical properties of these compounds. Transmittance spectra, HOMO and LUMO refer to the highest occupied molecular orbital and the lowest unoccupied molecular orbital respectively band gaps of PPy, PPy/TiO2, and PPy/ZnO polymer nanocomposites are 3.8, 3.3 eV and 3.2 eV, respectively. All (PPy/TiO2 and PPy/ZnO) show a shift in the N–H peak of PPy. The change in stretched peak positions indicates the significant bond formed between PPy and TiO2 as well as ZnO. The bonding of TiO2 and ZnO with PPy polymers. Also observed TiO2 and ZnO are significantly at about (1100, 1300) cm−1 and (1500, 1900) cm−1, respectively.