Full inorganic cesium lead halide perovskites (IOPs) are regarded as attractive candidates for light-emitting diodes (LEDs) by their excellent luminescent conversion. However, unsatisfactory efficiency and stability are still the main drawbacks that hinder the commercialization progress of perovskite LEDs (PeLEDs). Here, we report an extremely uniform and flat CsPbBr₃ film composing of self-assembly core–shell structured quantum dots (SCQDs) based on one-step precursor coating. The QDs size in the CsPbBr₃ film is around 4.5 nm (smaller than the Bohr radius), which significantly confines injected carriers and leads to a ultrahigh exciton binding energy (E_b) of 198 meV. In addition, unfavorable surfacial defects are dramatically passivated by a thin surfacial-capping layer composed of long-chain ammonium groups (phenylalanine bromide, PPABr), resulting in an ultralow nonradiative recombination rate. Consequently, the CsPbBr₃ SCQDs film presents a high photoluminescence quantum yield (PLQY) of 85%. It enables the resulting green PeLEDs to deliver a recorded external quantum efficiency (EQE) over 15% with ideal operational stability. Furthermore, the developed CsPbBr₃ SCQDs film also demonstrates promising potential in multifunctional lighting sources such as flexible and smart devices.

中文翻译：

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自组装的高品质CsPbBr ₃量子点薄膜对高效发光二极管的应用

全无机卤化铯铅钙钛矿（IOP）具有出色的发光转换性能，因此被认为是发光二极管（LED）的有吸引力的候选材料。然而，令人满意的效率和稳定性仍然是阻碍钙钛矿LED（PeLED）的商业化进程的主要缺点。在这里，我们报道了一种非常均匀且平坦的CsPbBr ₃膜，该膜由基于一步前体涂层的自组装核-壳结构量子点（SCQD）组成。CsPbBr ₃薄膜中的QDs尺寸约为4.5 nm（小于玻尔半径），这大大限制了注入的载流子，并导致了超高的激子结合能（E _b）的198 meV。此外，由长链铵基团（苯丙氨酸溴化物，PPABr）组成的薄表面覆盖层可显着钝化不利的表面缺陷，从而导致超低的非辐射复合率。因此，CsPbBr ₃ SCQDs薄膜呈现出85％的高光致发光量子产率（PLQY）。它使最终的绿色PeLED能够提供超过15％的已记录外部量子效率（EQE），并具有理想的操作稳定性。此外，已开发的CsPbBr ₃ SCQDs膜还展示了在多功能光源（如柔性和智能设备）中的有希望的潜力。