Blue-emitting materials and their light-emitting diodes (LEDs) are always challenging in lighting and display applications. Recently, perovskite LEDs (PeLEDs) with efficient and stable green/red emission have made great progress, where external quantum efficiency (EQE) over 20% has been reached. However, it is still a big challenge to realize stable blue PeLEDs with high efficiency mainly because of the poor film quality and unreasonable device structure. Herein, a cocktail strategy, that is, multication (Cs/Rb/FA/PEA/K)Pb(Cl/Br)₃, is demonstrated to improve both the efficiency and stability of blue PeLEDs. Combined with the “insulator–perovskite–insulator” structure, PeLEDs based on a multication (Cs/Rb/FA/PEA/K)Pb(Cl/Br)₃ perovskite film show maximum EQE of 2.01% and maximum luminance of 4015 cd/m² at 484 nm. More importantly, the device exhibits robust durability, and its half-lifetime is over 300 min under continuous operation. The multication strategy could open up a new avenue for the design of new blue-emitting materials for high-performing PeLEDs.

中文翻译：

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无机卤化物钙钛矿中多种阳离子向高效和高度稳定的蓝色发光二极管的鸡尾酒。

在照明和显示应用中，发蓝光的材料及其发光二极管（LED）始终具有挑战性。近来，具有高效和稳定的绿色/红色发射的钙钛矿LED（PeLED）取得了长足的进步，其中外部量子效率（EQE）已达到20％以上。但是，要实现高效率的稳定蓝色PeLED仍然是一个很大的挑战，这主要是由于薄膜质量差和器件结构不合理。在本文中，证明了混合策略，即多阳离子（Cs / Rb / FA / PEA / K）Pb（Cl / Br）₃，可以提高蓝色PeLED的效率和稳定性。结合“绝缘体-钙钛矿-绝缘体”结构，基于多阳离子（Cs / Rb / FA / PEA / K）Pb（Cl / Br）的PeLED ₃钙钛矿薄膜在484 nm处的最大EQE为2.01％，最大亮度为4015 cd / m ²。更重要的是，该设备具有强大的耐用性，并且在连续操作下其半衰期超过300分钟。多重阳离子化策略可以为高性能PeLED的新型蓝色发光材料设计开辟新途径。