Density Functional Theory Analysis of Structural, Electronic, and Optical Properties of Mixed-Halide Orthorhombic Inorganic Perovskites

Abstract

Inorganic metal-halide perovskites hold a lot of promise for solar cells, light-emitting diodes, and lasers. A thorough investigation of their optoelectronic properties is ongoing. In this study, the accurate modified Becke Johnson generalized gradient approximation (mBJ-GGA) method without/with spin orbital coupling (SOC) implemented in the WIEN2k code was used to investigate the effect of mixed I/Br and Br/Cl on the electronic and optical properties of orthorhombic CsPb­(I1–x Br x )3 and CsPb­(Br1–x Cl x )3 perovskites, while the Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA) method was used to investigate their structural properties. The calculated band gap (E g) using the mBJ-GGA method was in good agreement with the experimental values reported, and it increased clearly from 1.983 eV for CsPbI3 to 2.420 and 3.325 eV for CsPbBr3 and CsPbCl3, respectively. The corrected mBJ + SOC E g value is 1.850 eV for CsPbI3, which increased to 2.480 and 3.130 eV for CsPbBr3 and CsPbCl3, respectively. The calculated photoabsorption coefficients show a blue shift in absorption, indicating that these perovskites are suitable for optical and optoelectronic devices.

Ab-initio study of the effect of bromide mixing into RbPbI$_3$ on the structural, electronic and optical properties

“…The lowest band gap is observed for the equal mixture of I and Br. The band gap estimated with TB-mBJ potential agrees well with the experimental values for the halide mixed CsPbI 3 systems [50]. TB-mBJ potential uplifts the CBM towards the higher energy and thus, widens the band gap values.…”

Amplified Spontaneous Emission from Thermally Evaporated High-Quality Thin Films of CsPb(Br1–xYx)3 (Y = I, Cl) Perovskites

“…To characterize the structural configurations of the fabricated mixed inorganic perovskites thin films, X-ray diffraction (XRD) analysis was performed to evaluate the crystallinity of the perovskite thin films, as shown in Figure . The inorganic CsPb­(Br 1– x Y x ) 3 perovskites have an orthorhombic structure as illustrated in previous work. − In the XRD spectra, the diffraction peaks of CsPbI 3 gradually shifted toward those of CsPbBr 3 and CsPbCl 3 as x was increased from 0.00 to 1.00. The XRD pattern of pure CsPbI 3 shows several diffraction peaks, specifically, peaks at 14.41, 20.68, 23.08, 24.11, 29.03, 32.97, and 35.99°.…”

Lead-Free Double Perovskite Cs2NaErCl6: Li+ as High-Stability Anodes for Li-Ion Batteries

“…Then, the system energies based on the other two positions are also calculated, including Li + doped into the lattice gap and Li + doped into the octahedron formed by a cation and a halogen ion (Figure S4 for the specific calculation model). In order to make the calculation results more accurate, 2 × 2 × 2 superlattices are constructed and calculated by GGA and PBE functions . The system energies of three different doping positions are compared to determine which position the doped Li + tends to enter.…”

“…In order to make the calculation results more accurate, 2 × 2 × 2 superlattices are constructed and calculated by GGA and PBE functions. 31 The system energies of three different doping positions are compared to determine which position the doped Li + tends to enter. The calculation results show that the system energy of Li + entering the double perovskite lattice gap is the lowest, as shown in Figure 5a.…”