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Description
Hybrid organic–inorganic perovskites offer versatile platforms for tuning light emission through their chemical composition and structural dimensionality. However, achieving tunable broadband emission in single-phase lead iodide systems remains challenging. In this work, we present the synthesis, structural characterization, and optical properties of a two-dimensional hybrid perovskite, (L-cysH)PbI3·H2O, incorporating L-cysteinium cations (L-CysH). Its crystal structure comprises inorganic layers of corner- and edge-sharing PbI6 octahedra, separated by organic cations and water molecules connected through an extensive hydrogen-bonding network. Optical absorption measurements yield a band gap of 2.53 eV. Under 377 nm excitation at 78 K, the compound exhibits dual-band photoluminescence comprising a relatively narrow peak near 473 nm and a broad band centered at approximately 534 nm, tentatively attributed to free and self-trapped excitons, respectively. Cooling from 238 to 78 K increases the integrated emission intensity approximately 27-fold and shifts the CIE chromaticity coordinates from (0.342, 0.399) to (0.385, 0.473), demonstrating thermally tunable emission. Arrhenius analysis yields a thermal-quenching activation energy of 72.3 meV. Density functional theory calculations reveal an indirect fundamental band gap with a nearby direct transition and band-edge states predominantly derived from the inorganic lead iodide framework. The combined results highlight amino-acid-based hybrid perovskites as a platform for exploring temperature-responsive luminescence without halide mixing or extrinsic luminescent dopants.
References:
Sirenko, V. Y., Kucheriv, O. I., Shova, S. & Gural’skiy, I. A. Cysteine-Based Hybrid Perovskite Exhibiting Thermally Tunable Dual-Band Photoluminescence. Inorg. Chem. 65, 21837–21848 (2026).
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