Investigation of [C6H5CH2NH3]3BiCl6 organic-inorganic compound: From synthesis to functional characterization for UV-blocking optoelectronic application

A new lead-free organic–inorganic hybrid chlorobismuthate, (PMA) 3 BiCl 6 , was synthesized by slow evaporation at room temperature. Powder X-ray diffraction analysis refined by the Le Bail method confirms the formation of a well-crystallized orthorhombic phase indexed in the non-centrosymmetric space group P2 1 2 1 2 1 , providing the structural basis for the subsequent property investigations. Consistently, thermal analysis reveals good stability up to 266 °C, indicating the robustness of the hybrid framework. Based on this stable crystalline structure, optical measurements show a direct band gap of 3.13 eV, confirming the wide-band-gap semiconductor character of the compound, while the Urbach energy of 0.37 eV indicates a moderate degree of structural and electronic disorder near the band edge. To further understand the dielectric and charge-transport behavior, electrical measurements were performed between 40 and 200 °C. The dielectric response reveals a high relative permittivity, reaching approximately ε′ r ≈ 627 at 500 Hz near the upper temperature limit, suggesting a dielectric anomaly. In parallel, impedance and modulus analyses evidence coupled resistive–capacitive contributions and non-Debye-type relaxation behavior. The frequency-dependent AC conductivity shows a dispersive behavior dominated by localized charge carrier transport, with an activation energy of 0.961 eV determined at 50 kHz. Overall, the correlation between structural order, thermal robustness, wide-band-gap behavior, and thermally activated dielectric/electrical response highlights (PMA) 3 BiCl 6 as a promising lead-free hybrid material for UV-filtering and photovoltaic protection applications.