Bright perovskite nanocrystals with high color purity are promising for high-definition displays; however, their complex postprocessing process limits their large-scale production. Using a trace of octylamine to regulate the dynamic balance between surface ligand adsorption and desorption, we develop a facile method to obtain stable CsPbI₃ nanocrystal films that combine excellent optical and electrical properties. The octylamine additive maintains the integrity of nanocrystals and inhibits the formation of defects, greatly enhances the phase- and the photoluminescence-stability, and thus the operational stability of the corresponding light-emitting devices (LEDs); enables in situ substitution of oleylamine, which reduces the spacing between adjacent nanocrystals and thus leads to closely packed nanocrystal films with promoted charge carrier transport capability; and also increases the activation energy for ion migration, indicating that the number of ion vacancies─namely, the ion migration paths─has been decreased. As a result, the octylamine additive leads to a 4- and 6-fold increase in LED external quantum efficiency (EQE) and operational lifetime, respectively. LEDs based on octylamine-assisted Zn-doped CsPbI₃ nanocrystals show a high EQE of 15.3%.

中文翻译：

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通过辛胺的配体工程提高 CsPbI3 纳米晶基发光二极管的效率和稳定性

具有高色纯度的明亮钙钛矿纳米晶体有望用于高清显示器；然而，它们复杂的后处理过程限制了它们的大规模生产。使用微量辛胺调节表面配体吸附和解吸之间的动态平衡，我们开发了一种简便的方法来获得稳定的 CsPbI ₃结合了优异的光学和电学性能的纳米晶体薄膜。辛胺添加剂保持纳米晶体的完整性并抑制缺陷的形成，大大提高了相位和光致发光的稳定性，从而提高了相应发光器件（LED）的工作稳定性；能够原位取代油胺，这减少了相邻纳米晶体之间的间距，从而导致紧密堆积的纳米晶体薄膜具有提高的电荷载流子传输能力；并且也增加了离子迁移的活化能，表明离子空位的数量 - 即离子迁移路径 - 已经减少。因此，辛胺添加剂导致 LED 外部量子效率 (EQE) 和使用寿命分别增加 4 倍和 6 倍。_{3 个}纳米晶体显示出 15.3% 的高 EQE。