Thermal Quenching Resistance in Dielectrically Confined Quantum Perovskites via Dual Passivation for Temperature‐Resistant White Light Emitting Diodes

Abstract 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 MAPbX ₃ (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 –CF ₂ groups in electroactive PVDF effectively passivates shallow halide vacancies and undercoordinated Pb ² ⁺ centres, while preserving the crystallinity of the perovskite film. This co‐crystallization‐driven spatial confinement of MAPbX ₃ (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: PbX ₂ ratio (4MABr _1‐x I _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.