Quasi‐two‐dimensional (quasi‐2D) perovskites, consisting of multi‐quantum wells (MQWs) separated by organic intercalating cations, exhibit high luminescence efficiency while the photophysical processes involved remain partially obscure due to the uncertainty of the MQWs structure. Herein, a synergetic dual‐additive strategy is adopted to prepare quasi‐2D perovskite films, where 18‐crown‐6 and tris(4‐fluorophenyl)phosphine oxide are utilized to suppress the formation of low‐dimensional perovskites, diminish defect density, and enhance photoluminescence quantum yield to 93.7%. Notably, a long‐lived delayed component, spanning hundreds of microseconds, is identified for the first time in perovskite emitters, which correlates with exciton dissociation and recombination, and the differences in temperature‐dependent radiative lifetime of the delayed components match with the luminescence properties. Finally, benefiting from lower trap density and more efficient energy‐funneling, green PeLEDs treated with dual additives have achieved a high external quantum efficiency of 28.9% and a commendable operating half‐lifetime of 17.8 h at an initial brightness of 500 cd m−2. The observation of the long‐lived delayed components, coupled with insights into exciton dissociation, provides a profound and comprehensive understanding of the fundamental carrier behavior in perovskite emitters and establishes a direct correlation between the properties of perovskite emitters and their photophysical processes.

中文翻译：

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高效准二维绿色钙钛矿发光二极管中的激子解离和长寿命延迟元件


准二维 （quasi-2D） 钙钛矿由有机插层阳离子分离的多量子阱 （MQW） 组成，表现出高发光效率，而由于 MQWs 结构的不确定性，所涉及的光物理过程仍然部分模糊。在此，采用协同双加成策略制备准 2D 钙钛矿薄膜，其中 18-冠-6 和三（4-氟苯基）氧化膦用于抑制低维钙钛矿的形成，降低缺陷密度，并将光致发光量子产率提高到 93.7%。值得注意的是，在钙钛矿发射器中首次发现了跨越数百微秒的长寿命延迟分量，它与激子解离和复合相关，并且延迟分量的温度相关辐射寿命的差异与发光特性相匹配。最后，受益于较低的陷阱密度和更高效的能量漏斗，用双重添加剂处理的绿色 PeLED 在 500 cd m-2 的初始亮度下实现了 28.9% 的高外部量子效率和 17.8 小时的值得称赞的工作半衰期 17.8 小时。对长寿命延迟成分的观察，加上对激子解离的见解，为钙钛矿发射器的基本载流子行为提供了深刻而全面的理解，并在钙钛矿发射器的特性与其光物理过程之间建立了直接关联。