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Utilizing first-principles calculations, this study explores the physical characteristics of K2BGaI6 (B = Tl, Rb) double perovskites with the objective of gaining a deeper understanding of their viability for renewable applications. In evaluating the phase stability, we calculated the formation enthalpies, tolerance factor and optimization energies, demonstrating that both compounds exhibit stability and are conducive to experimental synthesis. The semiconducting nature of perovskites is manifested through an energy gap, with values of 1.11 eV at (L–X) for K2TlGaI6 and 1.2 eV at (L–L) for K2RbGaI6, which is also reflected from density of states. Both perovskites display ductile characteristics, but the hardness factor indicates greater strength for K2RbGaI6. The Kleinman parameter value for K2RbGaI6 and K2TlGaI6 indicates a prevalence of bond stretching. The Debye and melting temperatures of K2RbGaI6 surpass that of K2TlGaI6. The assessment of optical response involves examining various parameters that reveal absorption in both the visible and UV regions. The thermoelectric response is gauged by examining prominent values in electrical conductivity, Seebeck, and ZT parameters at high elevated temperatures. The collective findings favor the utilization of K2BGaI6 (B = Tl, Rb) perovskites in environmentally friendly technologies. [ABSTRACT FROM AUTHOR]

The perovskite crystals formed by methylammonium lead iodide (MAPbI3) have garnered growing interest owing to their exceptional photovoltaic capabilities, economical production process, and ability to be processed in solution. A multitude of techniques have been devised to produce dense and uniform perovskite thin coatings, which are critical for the proper functioning of electronic devices. In order to promote the development of CH3NH3PbI3 perovskite thin films that are uniform, dense, and exceptionally smooth, we present an additive-assisted method utilizing Copper zinc tin sulfide Cu2ZnSnS4 (CZTS) nanoparticles. The surface, optical, morphological, and structural properties were subsequently determined. The mechanisms by which the additive improves the quality of the material during the formation of CH3NH3PbI3 perovskite films are elucidated in this study. These processes are postulated to characterize the crystallization of the films. Using this beneficial technique, a high-quality CH3NH3PbI3 film with a grain size significantly larger than 1.6 μm was effectively manufactured. Additionally, the doping process resulted in enhancements in both absorption and photoluminescence intensity. The addition of CZTS NPs elevated the crystal structures and morphologies of the CH3NH3PbI3 layer to a degree that was comparatively favorable. This was evidenced by the crystallite size of 83 nm and an optical bandgap (Eg) of 1.63 eV, both of which attest to the enhanced quality of the film. With the structure of glass/FTO/TiO2/CH3NH3PbI3:CZTS NPs/spiro-oMeTAD/Au ,the power conversion efficiency (PCE) of the best cell was 15.13% with a fill factor of 66.07%. The results of this study indicate that doping CH3NH3PbI3 solar cells with CZTS NPs is a dependable method for enhancing photovoltaic performance and promoting crystal growth. [ABSTRACT FROM AUTHOR]

The switch to sustainable power generation sources has gained substantial spotlight due to the essential need to decrease fossil fuels dependence, and alleviate climate change issues. This research aims to explore the first principle calculations for geometrical structure, enthalpy of formation, electronic structure behavior, optical spectra, and photocatalytic performance of the clean new Iodine-based triple perovskite compounds A3B2I9 (A = Rb or Cs, and B = Sb or Bi) using FP-LAPW method based on the density functional theory implemented in Wien2K software. The outcomes prove that these triple perovskite compounds can be formed spontaneously under standard conditions, because they are thermodynamically stable. Moreover, the electronic band structure shows an indirect semiconductor behavior of all studied compounds. Further, the optical spectra highlights that all studied compounds have high visible light absorption due to their suitable forbidden band values [1.8 eV–2.369 eV] which facilitate efficient electron–hole pairs generation maximizing the conversion of light into electrical energy. In addition, all studied compounds are satisfied the limits necessary to split water and then to produce hydrogen. Consequently, these compounds are most likely to be used as Lead-free perovskites in various optoelectronic applications, especially solar cells and hydrogen production from water splitting. [ABSTRACT FROM AUTHOR]

Halide perovskite materials have received significant attention of researchers in various applications, such as solar cells, batteries, supercapacitors, and particularly sensors. In this study, CsPbBr3/p-Si heterojunction thin film was successfully fabricates by facile thermal evaporation, and comprehensively investigates the impact of gamma irradiation (0 to 75 kGy) on the structural, morphological, optical, and I-V characteristics. The structural parameters measured via XRD confirm the formation of orthorhombic phase, and the crystallite size increases while micro-strain decreases with increasing irradiation. FE-SEM experiments reveal a CsPbBr3 thin-film cross section of approximately 233 nm and confirm the variation in grain size with irradiation, and EDX analyses confirm the purity and quality of the thin film. From optical perspective, a notable decline in the energy bandgap from 2.38 eV to 2.20 eV was observed with increasing irradiation dose, which is caused by the increase in crystallite size and formation of defects. Furthermore, current–voltage (I-V) measurements suggest an increase in the saturation current, whereas the ideality factor, barrier height, and series resistance exhibit a diminishing trend with increasing gamma exposure. The gamma-induced structural defects significantly influenced CsPbBr3/p-Si heterojunction thin film characteristics, highlighting its potential for advanced sensing applications. [ABSTRACT FROM AUTHOR]

Luminescent mesoporous Tb(OH)3@SiO2 core-shell nanospheres were synthesized through W/O microemulsion process at ambient temperature. The negatively charged silica favors a coating of the positively charged Tb3+ composite. Thus, silicon layer was adsorbed on the surface of Tb(OH)3 groups to form Tb-O-Si through electrostatic interaction. X-ray diffraction, field emission transmission electron microscopy (FE-TEM), energy-dispersive X-ray spectrometry, and Fourier transform infrared, UV/Visible, and photoluminescence spectroscopies were applied to examine the phase purity, crystallinity, surface morphology, and optical properties of the core-shell nanospheres. The FE-TEM results have revealed typically ordered mesoporous characteristics of the material with monodisperse spherical morphology in a narrow size distribution. The luminescent mesoporous core-shell nanospheres exposed remarkable splitting with broadening in the emission transition 5D4 → 7F5 (543 nm). In addition, the luminescent mesoporous core-shell nanospheres emit strong green fluorescence (from Tb3+) in the middle of the visible region under 325 nm (3.8) excitation. The luminescent mesoporous Tb(OH)3@SiO2 core-shell nanospheres can therefore be exploited as fluorescent probes in biomarkers or biolabeling, optical sensing, and drug delivery system. Further, these nanospheres could have potential use as scattering layers in dye-sensitized solar cells. [ABSTRACT FROM AUTHOR]

Magnetic materials possess the capability to generate magnetic fields, which facilitates the effective conversion of energy, storage of information, and transmission in contemporary electronic systems. The present study includes the spin-polarized computation on the mechanical, structural, thermodynamic, optical and transport characteristics of Rb2NaMoX6 (X = Br, I). The studied perovskites are found to be stable structurally, mechanically and thermodynamically. An energy gap in both spin channels appears on the (X–X) symmetry lines, suggesting a direct gap for both perovskites. A high magnetic moment of 3 μB\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${\upmu }_{\text{B}}$$\end{document} is attained for Rb2NaMoX6 (X = Br, I) which favors their potential applications in spintronics. Elastic attributes depict that Rb2NaMoBr6 is ductile, while Rb2NaMoI6 is brittle. The Rb2NaMoBr6 exhibits high value of θD\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${\uptheta }_{\text{D}}$$\end{document}, showing its stiffer nature than Rb2NaMoI6. Optical absorption in UV range for Rb2NaMoBr6 and in visible range for Rb2NaMoI6 is the indicator to utilize these materials for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Double perovskites based on rubidium have demonstrated potential for obtaining high solar cell power conversion efficiencies. Their distinct crystal structure and electrical characteristics influence these materials’ potential as effective light absorbers. In this present manuscript, a detailed scrutiny of the physical aspects of halide perovskites Rb2TlAsI6 and Rb2TlGaI6 is presented using density functional theory framework implanted in Wien2K code using. Modified Becke Johnson potential is employed to treat the exchange–correlation effects. A computed tolerance factor, octahedral tilting, and formation energy ensure the structural and thermodynamic stability of given structures. Three independent elastic constants and mechanical properties were computed using the Thomas Charpin method. Ductile nature of Rb2TlAsI6 and brittle nature for Rb2TlGaI6 is revealed from computed mechanical attributes. The Debye temperature for Rb2TlGaI6 (171.32 K) is noted higher than Rb2TlAsI6 (144.53 K). Electronic properties revealed a direct bandgap (1.09 eV) for Rb2TlAsI6 and an indirect bandgap (1.2 eV) for Rb2TlGaI6. Optical properties indicate high polarization and absorption of incident light, which is suitable for photovoltaic applications in the visible spectrum. [ABSTRACT FROM AUTHOR]