DFT study of the structural, electronic and optoelectronic properties of PDAPb(I_1−x Br _x )₄ perovskites

Abstract

PDAPb(I1−xBrx)4 (NH3CH2CH2CH2NH3Pb(I1−xBrx)4, 0 ≤ x ≤ 1) is a two-dimensional (2D) Dion-Jacobson (DJ) phase perovskite that has attracted extensive attention owing to its potential as a promising candidate for optoelectronic (OE) application. Herein, the structural, electronic, and optoelectronic properties of PDAPb(I1−xBrx)4 by gradually substituting I with Br at 1/4 intervals starting from PDAPbI4 based on the first-principles approach of density functional theory (DFT). With the increase in Br content, the crystal volume of PDAPb(I1−xBrx)4 decreases nonlinearly. The electronic structure shows the bandgap presents an increasing trend (PDAPbI4 (2.272 eV) - PDAPb(I0.5Br0.5)4 (2.475 eV) - PDAPbBr4 (2.678 eV)). The most stable structure that can be obtained from the calculated formation energy (Ef) is PDAPb(I0.5Br0.5)4. The partial density of states (PDOS) reveals that the contribution of electrons is mainly related to the [PbX6]4- (X = I, Br) octahedron. The organic molecule PDA is almost not involved in the conductivity. The optoelectronic properties indicates that the characteristic peaks of the optoelectronic parameters of PDAPb(I1-xBrx)4 coincide with the bandgap. The doping ratio of 0.5 not only has the largest dielectric coefficient, but also has good conductivity in the visible region. Therefore, PDAPb(I0.5Br0.5)4 is extremely promising for applications in optoelectronics industry. This study provides some theoretical guidance for experiments and the search for new efficient and environmentally friendly OE materials.