Density functional theory study of Br doped CsPbI₃ perovskite for photovoltaic and optoelectronic applications

Abstract

First-principle calculations were used to investigate the structural, optoelectronic, elastic and thermodynamic properties of Br-doped CsPbI3 perovskite material using GGA-PBE, SCAN, and LDA functionals. The computed lattice parameters are consistent with the experimental and theoretical calculations, reported in the literature. The band structure along with the electronic density of states indicated that CsPbI3-xBrx (x = 0, 1, 2, 3) materials are semiconductors with direct band gaps, as projected using the three functionals. The energy band gap of CsPbI3 was tuned by replacing I ions with Br ions, resulting in CsPbI2Br, CsPbBr2I, and CsPbBr3 materials. These perovskite materials were found to be mechanically stable, ductile in nature and elastically anisotropic. The results of optical parameters such as absorption coefficients, refractive index, optical conductivity, optical reflectivity, electron energy loss, and extinction coefficients were calculated and analysed. The thermodynamic parameters including heat capacity, and Debye temperature were calculated. The direct band gap and energy-dependent optical parameters especially the absorption coefficient in the infrared and visible region of these perovskites’ materials suggest that they might be candidates for potential use in photovoltaic solar cells and optoelectronic applications.

Lead-free Perovskites TlGeClxBr3-x (x=0,1,2,3) as Promising Materials for Solar Cell Application: a DFT Study

“…The narrow and direct bandgaps of the perovskites clearly imply that they are potential for applications in optoelectronic devices which include perovskite solar cells. The slight decrease in the energy gap values as a result of changing a halogen anion with its counterparts with larger radii was also observed in other halide perovskites including CsPbClxBr3-x (x=0,1,2,3) perovskites [93], CsPbBr3−yIy (y = 0, 1, 2, 3) [96], CsPbCl3−yIy (y = 0, 1, 2, 3) [97], CsPbBr3-xYx(Y=I, Cl) [98], KGeI3-xBrx [99], MAPb (BrxI3-x)3 [100], and CsPbI3−xBrx (x = 0, 1, 2, 3) perovskites [101]. As discussed in the previous section, replacing Cl with Br leads to an increase in the materials' optimized lattice constants, which is also accompanied by a decrease in their electronic band gaps.…”

‘Out of the glovebox’ studies of a multifunctional [Gd3+‐Ho3+‐Dy3+]:CsPbI2.7Br0.3 perovskite semiconductor system for energy applications

“…Among these, doping utilizing the impurity of another substance is adopted on a larger scale because it is a facile and sustainable method of improving the characteristics of the host material. 24,25 In addition to doping, various aspects associated with perovskite modification have been explored previously. In this regard, the rigorously used methods are additive and include interface engineering, compositional variation, passivation, optimization in terms of thermal curing, and defect controlling.…”

“…Compositional engineering using different approaches has been one of such modification strategies. Among these, doping utilizing the impurity of another substance is adopted on a larger scale because it is a facile and sustainable method of improving the characteristics of the host material 24,25 . In addition to doping, various aspects associated with perovskite modification have been explored previously.…”

Phase Separation of Br-Doped CsPbI3: A Combined Cluster Expansion, Monte Carlo, and DFT Study

“…These halides provide an effective means of adjusting the band gap of these perovskites. For instance, the energy band gap can be changed from 1.5–2.0 eV by varying the types of halide ions present in the material [ 6 , 7 , 8 ]. By controlling the energy band gap, the absorption edge of the perovskite may be adjusted, which allows optimization of the efficiency and performance of the device.…”