Metal halide perovskites nanocrystals (NCs) are emerging as competitive alternatives for semiconductor NCs in the fields of consumer optoelectronic devices; however, boosting their long-term stability still needs extensive study. Encapsulation of perovskite NCs with polymer becomes a promising strategy, yet the dielectric screening effect on the excitons of perovskites from the polymer matrix has seldom been considered. Here, we demonstrated this effect in high-permittivity poly(vinylidene fluoride) (PVDF) encapsulated CsPbBr₃ (CPB) crystals CPB/PVDF composites films. The in situ nonuniform growth mechanism of CPB crystal with respect to its concentration in the precursor was revealed from multiscale structure observations. Comprehensive physical properties of CPB/PVDF composites with varying CPB concentrations were thoroughly investigated. The luminescence of the composites films Composite films made from precursors with CPB concentration increasing to saturation all showed bright luminescence, and an exceptional long fluorescence lifetime up to τ_avg=731 ns was observed, much superior to other polymers with lower permittivity encapsulated CPB composites. The stable luminescence is understood from the strong interplay between electron-hole Coulomb interactions in CPB and its surrounding high-permittivity PVDF. Meanwhile, the interfacial interaction between CPB and PVDF greatly influenced the crystallization behavior of PVDF polymer at nanoscale, thus altered the dielectric and mechanical properties of CPB/PVDF composite films accordingly. Finally, a warm white light-emitting diode device was assembled based on green light emitting CPB/PVDF film, positively implying its potential application in high-performance optoelectronic devices.

金属卤化物钙钛矿纳米晶体（NCs）正在成为消费光电子器件领域中半导体NCs的竞争替代品。但是，提高其长期稳定性仍需要大量研究。用聚合物包封钙钛矿NCs成为一种有前途的策略，但是很少考虑从聚合物基质中对钙钛矿激子进行介电屏蔽作用。在这里，我们在高介电常数聚偏二氟乙烯（PVDF）封装的CsPbBr ₃（CPB）晶体CPB / PVDF复合膜中证明了这种效果。在原位从多尺度结构观察中揭示了CPB晶体相对于其在前体中的浓度的不均匀生长机理。彻底研究了不同CPB浓度的CPB / PVDF复合材料的综合物理性能。复合膜的发光由CPB浓度增加到饱和的前体制成的复合膜均显示出明亮的发光，并具有长达_τavg的超长荧光寿命观察到= 731 ns，远远优于其他具有较低介电常数封装CPB复合材料的聚合物。从CPB中的电子-空穴库仑相互作用与其周围的高介电常数PVDF之间的强烈相互作用可以了解稳定的发光。同时，CPB和PVDF之间的界面相互作用极大地影响了PVDF聚合物在纳米级的结晶行为，从而相应地改变了CPB / PVDF复合膜的介电和力学性能。最后，基于绿色发光CPB / PVDF薄膜组装了暖白色发光二极管器件，这肯定表明了其在高性能光电器件中的潜在应用。