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In this study, we investigated the optoelectronic properties of cubic (Pm3m) and orthorhombic (Pnma) CsPbX3 (X = I, Br, and Cl). We utilized the full potential linear augmented plane wave method, which is implemented in the WIEN2k code, to facilitate the investigation. Different exchange potentials were used to analyze the optoelectronic behavior using the available density functional theory methods. Our findings revealed that CsPbX3 perovskites display direct band gaps at the R and Г points for cubic (Pm3m) and orthorhombic (Pnma) structures, respectively. Among the exchange potentials, the mBJ-GGA method provided the most accurate results. These outcomes concurred with the experimental results. In both Pm3m and Pnma structures, interesting changes were observed when iodide (I) was replaced with bromine (Br) and then chlorine (Cl). The direct band gap at the R and Г points shifted to higher energy levels. Similarly, when I was replaced with Br and Cl, there was a noticeable decrease in the absorption coefficient, dielectric constants, refractive index, and reflectivity, in addition to a band gap shift to higher energy levels. [ABSTRACT FROM AUTHOR]

The structural, electronic, and optical properties of inorganic CsPb(I1−xBrx)3 compounds were investigated using the full-potential linear augmented-plane wave (FP-LAPW) scheme with a generalized gradient approximation (GGA). Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA) and modified Becke–Johnson GGA (mBJ-GGA) potentials were used to study the electronic and optical properties. The band gaps calculated using the mBJ-GGA method gave the best agreement with experimentally reported values. CsPb(I1−xBrx)3 compounds were wide and direct band gap semiconductors, with a band gap located at the M point. The spectral weight (SW) approach was used to unfold the band structure. By substituting iodide with bromide, an increase in the band gap energy (Eg) values of 0.30 and 0.55 eV, using PBE-GGA and mBJ-GGA potentials, respectively, was observed, whereas the optical property parameters, which were also investigated, demonstrated the reverse effect. The high absorption spectra in the ultraviolet−visible energy range demonstrated that CsPb(I1−xBrx)3 perovskite could be used in optical and optoelectronic devices by partly replacing iodide with bromide. [ABSTRACT FROM AUTHOR]

• The structural, elastic, electronic, magnetic, and optical properties of vacancy-ordered Rb 2 TcCl 6 have been thoroughly examined through the use of first-principles calculations. • The stability of Rb 2 TcCl 6 is demonstrated by the formation energy, optimization curves and phonon curves. • The spin-plarized electronic band structure and density of states (DOS) predict the semiconductor nature in both spin states. • The obtained magnetic moments for Rb 2 TcCl 6 reveal the potential of for spintronics. • An optical band gap with maximum absorption reveals that this compound is also useful for the application in optoelectronics. Due to their versatile properties, vacancy-ordered double perovskites offer a wide range of potential uses due to their versatile properties. We have thoroughly examined the physical characteristics of vacancy-ordered Rb 2 TcCl 6 in its cubic phase by employing the spin-polarized computations. The ground state energy and optimum structural parameters are obtained in order to assess the structural stability, which is further validated using the tolerance factor and formation energy values. The ductile character of Rb 2 TcCl 6 is revealed by a comprehensive evaluation of mechanical properties. Vickers hardness factor suggests that Rb 2 TcCl 6 can withstand against pressure-induced disturbance more strongly. A direct bandgap for spin-up is measured up to 2.33 eV, while for spin-dn it is 2.02 eV. According to the magnetic moments of 2.69 μ B , Rb 2 TcCl 6 is an attractive material for spintronic devices. A number of optical parameters are determined. For optoelectronic applications, Rb 2 TcCl 6 is an excellent choice due to its strong polarization in the visible and ultraviolet regions, as shown by its optical characteristics. [ABSTRACT FROM AUTHOR]

The crystallization techniques of organic-inorganic hybrid perovskites (OIHP) are considered an effective method for light collector or light emitting applications. In this article, the optical band gap, electron-hole behavior, and energy band alignment are all key optoelectronic properties of crystalline perovskite structures studied in this study. For this reason, a perovskite solution was prepared in a single step and tetrahydrofuran (THF) was used as a solvent to dissolve both perovskite precursors. Rapid crystallization of perovskite in solution was observed, preventing the formation of homogenous perovskite thin films. Subsequently, the effect of THF solvent on the direct crystallization of MAPbI 3 perovskite without thermal annealing was investigated. Thermal annealing is considered necessary for perovskite crystal formation as it gives the molecules enough thermal energy to self-organize and form a well-ordered crystalline layer. The procedures that create perovskite crystals without thermal annealing give a novel method for room temperature film preparation (RT) and pave the way for the manufacture of low-cost, stable perovskite solar cells (PSCs). UV–vis absorption/reflectance, photoluminescence, XRD, and SEM were used to explore the effects of this approach on the optical and structural properties of MAPbI 3 perovskite thin films. • Crystallizing Growth of MAPbI 3 Perovskite Nanorod was demonstrated. • Perovskite precursor solution in THF is dried to form perovskite powder. • Fabrication of perovskite films without annealing. • Perovskite films were tested under ns laser. • The strong light emission allows the observation of ASE. [ABSTRACT FROM AUTHOR]

The structural, electronic, and optical features of CsPb(I 1-x Br x) 3 (x = 0, 0.25, 0.50, 0.75, and 1.0) compounds were evaluated using first-principles calculations based on the full-potential linear augmented plane wave (FP-LAPW). The ground-state properties were examined, with a focus on the structural, electronic, and optical properties of the compounds. The structural features were computed using the PBE-GGA potential, revealing that both the lattice constant and bulk modulus varied nonlinearly with respect to the bromide concentration. Theoretical X-ray diffraction analyses revealed peak shifts to larger angles when the average fraction of bromide incorporated increased, indicating shrinkage in the lattice. While the E g values were calculated using the PBE-GGA potential and resulted the 1.45, 1.43, 1.53, 1.50, and 1.77 eV values, the mBJ-GGA potential values resulted the 1.90, 1.81, 2.11, 2.12, and 2.50 eV for CsPbI 3 , CsPbI 2.75 Br 0.25 , CsPbI 1.5 Br 1.5 , CsPbI 0.25 Br 2.75 , and CsPbBr 3 respectively. In addition to that, the E g values of CsPbI 1.5 Br 1.5 which were calculated using other potentials: LDA and PBEsol potentials have resulted the 1.43 and 1.49 eV values, respectively. The E g of CsPb(I 1-x Br x) 3 obtained using mBJ-GGA potential has relatively matched with previously reported experimental values. The calculated effective masses are highly correlated with the energies of E g, the valence-band maximum (VBM), and conduction-band minimum (CBM). We observed that there was an increase, with small bowing parameters (b), in E g value as the Br concentration increases in the CsPb(I 1-x Br x) 3 compounds. The semiconductor characteristic was prominent in the observed band profiles when PBE-GGA and mBJ-GGA potentials were applied. Additionally, the optical properties were examined in details. The calculations indicate that the CsPb(I 1-x Br x) 3 compounds are promising candidates for optoelectronics. Image 1 • The structural, electrical and optical properties of CsPb(I 1-x Br x) 3 were investigated using the PBE-GGA and mBJ-GGA. • An increase in the band gap energy (Eg) values of 0.32 eV (PBE-GGA) and 0.60 eV (mBJ-GGA) when substituting I with Br. • The calculated band gap (Eg) values using the mBJ-GGA were better matched with the experimental values. • The effective masses of electron and hole were calculated using PBE-GGA and mBJ-GGA potentials. • All the optical properties of CsPb(I1-xBrx)3 were investigated using PBE-GGA and mBJ-GGA potentials in details. [ABSTRACT FROM AUTHOR]