Excess ammonium halides as composition additives are widely employed in perovskite light-emitting diodes (PeLEDs), aiming to achieve high performance by controlling crystallinity and passivating defects. However, an in-depth understanding of whether excess organoammonium components affect the film physical/electrical properties and the resultant device instability is still lacking. Here, the trade-off between the performance and stability in high-efficiency formamidinium lead iodide (FAPbI₃)-based PeLEDs with excess ammonium halides is pointed, and the underlying mechanism is explored. Systematic experimental and theoretical studies reveal that excess halide salt-induced ion-doping largely alters the PeLEDs properties (e.g., carrier injection, field-dependent ion-drifting, defect physics, and phase stability). A surface clean assisted cross-linking strategy is demonstrated to eliminate the adverse impact of composition modulation and boost the operational stability without sacrificing the efficiency, achieving a high efficiency of 23.6%, a high radiance of 964 W sr⁻¹ m⁻² (The highest value for FAPbI₃ based PeLEDs), and a prolong lifetime of 106.1 h at large direct current density (100 mA cm⁻²), concurrently. The findings uncovered an important link between excess halide salts and the device performance, providing a guideline for rational design of stable, bright, and high efficiency PeLEDs.

中文翻译：

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消除钙钛矿发光二极管中成分调制对超高亮度和稳定性的不利影响

过量的卤化铵作为成分添加剂广泛应用于钙钛矿发光二极管（PeLED）中，旨在通过控制结晶度和钝化缺陷来实现高性能。然而，对于过量的有机铵成分是否影响薄膜的物理/电性能以及由此产生的器件不稳定性仍然缺乏深入的了解。在此，指出了基于高效甲脒碘化铅 (FAPbI ₃ ) 的 PeLED 与过量卤化铵的性能和稳定性之间的权衡，并探讨了其潜在机制。系统的实验和理论研究表明，过量卤化物盐诱导的离子掺杂很大程度上改变了 PeLED 的特性（例如载流子注入、场依赖性离子漂移、缺陷物理和相稳定性）。表面清洁辅助交联策略被证明可以消除成分调制的不利影响并在不牺牲效率的情况下提高运行稳定性，实现了 23.6% 的高效率和 964 W sr ^-1  m ^-2的高辐射率（基于 FAPbI ₃的 PeLED的最高值），同时在大直流电流密度（100 mA cm ^-2）下延长寿命 106.1 h 。研究结果揭示了过量卤化物盐与器件性能之间的重要联系，为合理设计稳定、明亮和高效的 PeLED 提供了指导。