Quantum dot light‐emitting diodes (QLEDs) have emerged as promising candidates for next‐generation display technology, but the limited lifetime of QLEDs hampers their further commercialization. Despite extensive research that has been conducted for the last decades, the mechanism leading to the rapid degradation of QLEDs remains unclear. Here, the formation of hole traps is demonstrated as the critical reason for the degradation of QLEDs. Applying impedance measurements, an enhancement of the negative capacitance is observed and provides straightforward evidence for the formation of hole traps. The generated hole traps introduce additional trap‐assisted recombination of trapped holes with free electrons, as reflected by the evolution and voltage dependence of the electroluminescence spectra, leading to efficiency loss in degraded devices. By performing numerical simulations to model the degradation of QLEDs, the formation of hole traps is quantified as a function of aging time. The calculated hole trap density is consistent with that as measured from impedance spectroscopy, validating that the hole trap formation is the mechanism for the voltage drift and efficiency decrease of QLEDs under constant current stress.

中文翻译：

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电应力下量子点发光二极管中的空穴陷阱形成


量子点发光二极管 （QLED） 已成为下一代显示技术的有前途的候选者，但 QLED 的有限寿命阻碍了其进一步的商业化。尽管在过去几十年中进行了广泛的研究，但导致 QLED 快速降解的机制仍不清楚。在这里，空穴陷阱的形成被证明是 QLED 降解的关键原因。应用阻抗测量，观察到负电容的增加，并为空穴陷阱的形成提供了直接的证据。产生的空穴陷阱引入了额外的陷阱辅助陷阱空穴与自由电子的复合，这反映在电致发光光谱的演变和电压依赖性上，导致退化器件的效率损失。通过执行数值模拟来模拟 QLED 的降解，空穴陷阱的形成被量化为老化时间的函数。计算出的空穴陷阱密度与从阻抗谱测量的空穴陷阱密度一致，验证了空穴陷阱的形成是 QLED 在恒流应力下电压漂移和效率降低的机制。