Hafnium-Based Chiral 2D Organic–Inorganic Hybrid Metal Halides: Engineering Polarity and Nonlinear Optical Properties via Para-Substituent Effects

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 8, 2025

Two-dimensional (2D) organic–inorganic hybrid metal halides (OIMHs), characterized by noncentrosymmetric structures arising from the incorporation of chiral organic molecules that break inversion symmetry, have attracted significant attention. Particularly, chiral-polar 2D OIMHs offer a unique platform for multifunctional applications, as coexistence chirality and polarity enables simultaneous manifestation distinct properties such nonlinear optical (NLO) effects, circular dichroism (CD), ferroelectricity. In this study, we report first synthesis hafnium (Hf)-based OIMHs, achieved through strategic para-substituents on benzene ring components. By tuning substituents, successfully modulate crystal structures, resulting in both chiral-nonpolar systems. Our analysis structural properties, supported density functional theory calculations, demonstrates these materials can be systematically tuned, enabling adjustable band gaps CD UV range (200–280 nm). Notably, halogen substitution at para-position layer produces tunable ranging 4.33 to 4.48 eV, widest reported date OIMHs. Furthermore, exhibit enhanced NLO including remarkable 3.3-fold increase second-harmonic generation intensity compounds compared their counterparts. These findings position Hf-based promising candidates UV-region devices self-driven circularly polarized light detectors, offering new opportunities designing optoelectronic harnessing interplay between polarity.

Language: Английский

Effect of Halide Tuning on the Structural, Dielectric, and Optical Properties of Two-Dimensional 2-Chloroethylammonium Lead Halides

Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 26, 2025

Layered hybrid organic–inorganic lead halides have gained a lot of attention for optoelectronic applications. A notable subset within this category is perovskites comprising halogenated amines since they may exhibit reduced band gap or polar order. We synthesized three compounds 2-chloroethylammonium (CEA+) cations, with the chemical formula CEA2PbX4 (X = Cl, Br, I). X-ray diffraction studies show that at room temperature (RT), CEA2PbBr4 and CEA2PbI4 crystallize in Pbnm symmetry, ordered CEA+ cations. undergo one structural phase transition (PT) into disordered Pmnm near 315 360 K, respectively. CEA2PbCl4 shows different packing organic chains oriented perpendicularly to perovskite layers. It undergoes two PTs 332 203 K from high-temperature (HT) I4/mmm partially intermediate completely low-temperature (LT) unknown space group. All emit photoluminescence (PL): orange, yellow-green, yellow CEA2PbI4, CEA2PbCl4, CEA2PbBr4, respectively, bromide exhibits very high quantum efficiency 48%. Overall, our findings halide engineering strongly modulates hydrogen halogen bonding strength, affecting arrangement building units, molecular dynamics, thus properties.

Language: Английский

Protective layer engineering: Impact of SnO ₂ and PbI ₂ on the optical parameters and stability of hybrid perovskite thin films

Molecular Crystals and Liquid Crystals, Journal Year: 2025, Volume and Issue: unknown, P. 1 - 8

Published: Feb. 17, 2025

Language: Английский