Adopting proper electron transport layers (ETLs) is essential to high‐performance all‐inorganic perovskite light‐emitting diodes (PeLEDs). However, the effect of ETLs has not been comprehensively investigated in all‐inorganic nanocrystal PeLEDs, while 2,2′,2′′‐(1,3,5‐benzenetriyl) tris‐[1‐phenyl‐1H‐benzimidazole] (TPBi) is the most common ETL. Herein, a novel strategy is proposed to enhance the efficiency of nanocrystal PeLEDs. Tris(8‐hydroxyquinoline) aluminum (Alq₃) is incorporated into TPBi to form a new ETL TPBi/Alq₃/TPBi, simultaneously enabling charge balance and confinement. The green PeLED with new ETL exhibits a maximum external quantum efficiency (EQE) of 1.43%, current efficiency of 4.69 cd A⁻¹, and power efficiency of 1.84 lm W⁻¹, which are 191%, 192%, and 211% higher than those of PeLEDs with conventional ETL TPBi, respectively. Significantly, the EQE is 36‐fold higher than that of PeLED with high electron mobility ETL. Impressively, the full width at half‐maximum of electroluminescence emission is 16 nm, which is the narrowest among CsPbBr₃ PeLEDs. The findings may present a rational strategy to enhance the device engineering of all‐inorganic PeLEDs.

中文翻译：

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通过新的电子传输层实现的全无机钙钛矿纳米晶体的高效绿色发光二极管

采用适当的电子传输层（ETL）对于高性能全无机钙钛矿发光二极管（PeLED）是必不可少的。然而，ETLs的影响尚未在全无机纳米晶体PeLED中得到全面研究，而2,2'，2''-（1,3,5-苯三基）tris- [1-苯基-1H-苯并咪唑]（TPBi ）是最常见的ETL。在本文中，提出了一种新颖的策略来增强纳米晶PeLED的效率。TPBi中加入了Tris（8- hydroxyquinoline ）铝（Alq ₃）以形成新的ETL TPBi / Alq ₃ / TPBi，同时实现了电荷平衡和封闭。具有新ETL的绿色PeLED的最大外部量子效率（EQE）为1.43％，电流效率为4.69 cd A ^-1，功率效率为1.84 lm W ^-1，分别比具有传统ETL TPBi的PeLED高191％，192％和211％。值得注意的是，EQE比具有高电子迁移率ETL的PeLED高36倍。令人印象深刻的是，电致发光发射的半峰全宽为16 nm，是CsPbBr ₃ PeLED中最窄的。这些发现可能是增强所有无机PeLED器件工程设计的合理策略。