Thermal Quenching Resistance in Dielectrically Confined Quantum Perovskites via Dual Passivation for...

Thermally induced photoluminescence quenching remains at present a significant limitation in the commercialization of perovskite-based light-emitting diodes (PLEDs). Here, a dual-passivation strategy is reported that combines dielectric confinement and dynamic chemical defect mitigation to produce thermally robust, photoluminescent MAPbX₃ (X = Br^-, I^-) nanocrystals embedded within a ferroelectric polyvinylidene fluoride (PVDF) matrix with significantly enhanced thermal resistance and photoluminescence performance. The synergistic interaction between excess methylammonium halide (MAX) and dipolar -CF₂ groups in electroactive PVDF effectively passivates shallow halide vacancies and undercoordinated Pb²⁺ centres, while preserving the crystallinity of the perovskite film. This co-crystallization-driven spatial confinement of MAPbX₃ (X = Br^-, I^-) domains yields near-unity photoluminescent quantum yield (PLQY), broad color tunability (420-736 nm), and significantly reduced non-radiative losses. Temperature-dependent photoluminescence measurements reveal minimal quenching up to 170 °C, with both bromide and iodide composites maintaining robust emission across a broad thermal window. Moreover, the optimized 4:1 MAX: PbX₂ ratio (4MABr_1-xI_x) shows a broad and balanced emission across the visible spectrum with chromaticity coordinates (0.29,0.31) & (0.32,0.35). The composite achieves a high color rendering index (CRI = 84) and a correlated color temperature (CCT) of 7861K. The results establish a facile and scalable route to thermally stable, color-tunable perovskite emitters, opening up pathways for next-generation PLEDs, flexible lighting, and anti-counterfeiting technologies.