Zhao Shiqi, Bai Peng, Zhao Xiaofei, Li Guangru
Central Research Institute, BOE Technology Group Co., Ltd., Beijing 100176, China.
Nano Lett. 2024 Oct 7. doi: 10.1021/acs.nanolett.4c03673.
Parasitic emission or leakage emission caused by electron leakage to a hole transport layer in quantum-dot light-emitting diodes (QLEDs) critically impacts device efficiency and operational stability. The buildup dynamics of such emission channels, however, was insufficiently researched. Herein, we investigate transient electroluminescence dynamics of leakage emission in red/green/blue (R/G/B) QLEDs and reveal notable contrast for R and G. In RQLEDs, leakage emission exhibits delayed turning-on than primary emission, which is attributed to much slower filling up from lower-energy electron states and the initial quenching by nonradiative recombination with trapped holes. For GQLEDs, leakage emission turns on much more concurrently, and emission preferably starts from higher energy states. For R/G QLEDs, under varied offset voltage modulation, the current efficiency of primary emission is invert-correlated to leakage emission, reconfirming leakage emission as a loss indicator.
量子点发光二极管（QLED）中电子泄漏到空穴传输层引起的寄生发射或漏泄发射对器件效率和运行稳定性有着至关重要的影响。然而，此类发射通道的累积动力学尚未得到充分研究。在此，我们研究了红/绿/蓝（R/G/B）QLED中漏泄发射的瞬态电致发光动力学，并揭示了R和G之间的显著差异。在RQLED中，漏泄发射的开启比一次发射延迟，这归因于从低能电子态填充的速度要慢得多，以及与捕获的空穴进行非辐射复合导致的初始猝灭。对于GQLED，漏泄发射开启得更为同步，并且发射优选从高能态开始。对于R/G QLED，在不同的偏置电压调制下，一次发射的电流效率与漏泄发射呈反相关，再次证实漏泄发射是一个损耗指标。
