Bandgap Engineering through Fe Doping in Cs₂SnCl₆ Perovskite: Photoluminescence Characteristics and Electronic Structure Insights

Abstract

The potential use of vacancy ordered double halide perovskites Cs 2 SnX 6 , where X = Cl, Br, and I, has increased because of recent progress in bandgap engineering and material science, giving them designable photovoltaic applications. Here, we disclose the straightforward solvothermal approach to synthesize Fe-doped Cs 2 SnCl 6 perovskite. Both the pristine (Cs 2 SnCl 6 ) and Fe:Cs 2 SnCl 6 crystals show a cubic arrangement of crystals with Fm3̅ m space symmetry. A subsequent crystalline phase on doping is confirmed by the examination of the ( 220) XRD peak and the strong correlation between Rietveld refinement and the cubic phase. Fe 2+ ion doping allows for a steady room-temperature photoluminescence (PL) emission center at 440 nm by lowering the band gap to 3.1 eV. Notably, an optimal 5% Fe doping concentration manifests the highest PL intensity, reaching a remarkable photoluminescence quantum yield (PLQY) of up to 55%. However, beyond this threshold, concentration quenching diminishes the PL intensity, highlighting the delicate balance in doping effects. The Cs 2 SnCl 6 crystal lattice exhibits band splitting confirmed from density functional theory simulations. The anisotropic development results in a huge micrometer-sized nearly 10−20 μm truncated octahedral morphology, which is confirmed by SEM. This work not only advances the empirical understanding of Fe:Cs 2 SnCl 6 PL characteristics but also shows its potential for applications in various optoelectronic devices such as LEDs and solar cells. Moreover, the ability to tailor the bandgap in perovskite materials offers opportunities for improved efficiency and performance in these devices.

A-Cation-Dependent Excited State Charge Carrier Dynamics in Vacancy-Ordered Halide Perovskites: Insights from Computational and Machine Learning Models

“…Notably, these time scales exceed the corresponding nonradiative electron–hole recombination times, as illustrated in Table . These findings reveal that the harvested electronic energy by photoexcitation dissipates to phonon modes much faster than the radiative process, − resulting in poor emission in pristine VOHPs. , …”

Hydrothermal Synthesis and Characterization of WSe2 Nanosheets: A Promising Approach for Wearable Photodetector Applications

“…When electron–hole pairs recombine, they release energy in the form of photons with a wavelength of 610 nm, resulting in red PL emission. WSe 2 emits light at 610 nm when excited at 360 nm because the bandgap in its electronic structure dictates the energy levels and wavelengths of light that can be emitted during the recombination of electron–hole pairs. − This specific energy gap is responsible for the observed photoluminescence at 610 nm. Color emitted by 2D material is predicted by using Commission International del’Eclairage (CIE) chromaticity diagram. , The color chromaticity coordinates ( x, y ) of all the WSe 2 is estimated from the PL emission spectral data (λ exc = 360 nm).…”