All‐inorganic CsPbI3 perovskite is a promising emitter for deep‐red light‐emitting diodes (LEDs). However, presently fabricated CsPbI3 polycrystalline films are composed of island‐like polycrystals, encountering the problems of serious interface current leakage and low‐efficiency carrier radiative recombination. Here, a CsPbI3‐xBrx quantum dots (QDs) matrix encapsulated CsPbI3 polycrystal film is reported to address the low‐efficiency issue of island‐like CsPbI3 polycrystalline film applied in deep‐red LEDs. The developed QDs matrix encapsulation strategy has two benefits. One is the filling of void space in the island‐like CsPbI3 polycrystal film to suppress the interface current leakage. The other more important benefit is utilizing the strong carrier confinement effect of QDs to strengthen the formation of excitons in the composite film and thus improve the electroluminescence efficiency. Moreover, interesting grain growth is found between CsPbI3‐xBrx QDs and CsPbI3 polycrystals, which further enhances the exciton transfer effect brought by the QDs matrix and optoelectronic properties of the fabricated composite films. Based on the obtained high‐quality QDs/polycrystal composite films, efficient and bright deep‐red LEDs are achieved with a peak external quantum efficiency of 15.24% and a maximum luminance of 3691 cd m−2.

中文翻译：

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量子点矩阵封装 CsPbI3 多晶复合薄膜，用于高效、明亮的深红色发光二极管

全无机CsPbI3钙钛矿是一种很有前景的深红色发光二极管（LED）发射体。然而，目前制备的 CsPbI3多晶薄膜由岛状多晶组成，存在严重的界面漏电流和低效率的载流子辐射复合问题。这里，CsPbI3-x溴X量子点 (QD) 矩阵封装 CsPbI3据报道，多晶薄膜可解决岛状 CsPbI 的低效率问题3多晶薄膜在深红光LED中的应用所开发的量子点矩阵封装策略有两个好处。一是岛状CsPbI中空隙的填充3多晶薄膜抑制界面漏电流。另一个更重要的好处是利用量子点强大的载流子限制效应来加强复合薄膜中激子的形成，从而提高电致发光效率。此外，在 CsPbI 之间发现了有趣的晶粒生长3-x溴XQD 和 CsPbI3多晶，进一步增强了量子点基体带来的激子传输效应和所制备的复合薄膜的光电性能。基于所获得的高质量量子点/多晶复合薄膜，实现了高效、明亮的深红光LED，峰值外量子效率为15.24%，最大亮度为3691 cd m−2。