Perovskite quantum dot-based light-emitting diodes (QLEDs) have been considered as a promising luminescent technology due to high color purity and wide color gamut. However, the realization of high-performance QLED is still hindered by near-perfect quantum dots (QDs) with efficient and stable exciton recombination behavior. Here, we proposed a ligand compensation (LC) strategy to optimize the QDs by introducing a ligand pair of tri-n-octylphosphine (TOP) and CsBr. The ligand pair could enhance the clarity and colloidal stability of the QD ink, facilitating the fabrication of highly smooth films. On one hand, TOP engages in interactions with Pb and effectively passivates the surface uncoordinated Pb2+. On the other hand, the supplement of CsBr provides a Br-rich environment to reduce Br vacancies (VBr). Through LC, QD films possess a high photoluminescence quantum efficiency of 82% and a shallow hole level, which enables efficient exciton recombination. In addition, the LC makes QD films exhibit stable exciton combination behavior and electrical transport characteristics. Resultantly, the LC-optimized QLEDs show a maximum external quantum efficiency (EQE) of 24.7% and an operational lifetime T50 of 182 h at an initial luminance of 100 cd m−2, which is obviously higher than that of the control device (EQE of 15.8%, T50 of 11 h). The proposed LC strategy for optimizing perovskite QDs presents a novel concept for achieving high-performance QLEDs and holds great potential for widespread application in various optoelectronics.

中文翻译：

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配体补偿可在钙钛矿量子点中实现高效稳定的激子复合，从而实现高性能 QLED


基于钙钛矿量子点的发光二极管（QLED）由于高色纯度和宽色域而被认为是一种有前途的发光技术。然而，高性能QLED的实现仍然受到近乎完美的量子点（QD）高效稳定的激子复合行为的阻碍。在这里，我们提出了一种配体补偿（LC）策略，通过引入三正辛基膦（TOP）和CsBr的配体对来优化量子点。配体对可以提高QD墨水的透明度和胶体稳定性，有利于制造高度光滑的薄膜。一方面，TOP与Pb相互作用，有效钝化表面不配位的Pb2+。另一方面，CsBr的补充提供了富含Br的环境以减少Br空位（VBr）。通过液晶，QD 薄膜具有高达 82% 的光致发光量子效率和浅空穴能级，可实现高效的激子复合。此外，LC使QD薄膜表现出稳定的激子结合行为和电传输特性。结果，LC优化的QLED在初始亮度为100 cd m−2时表现出24.7%的最大外量子效率（EQE）和182 h的工作寿命T50，明显高于对照器件（EQE）。 15.8%，T50 11 小时）。所提出的用于优化钙钛矿量子点的液晶策略提出了实现高性能QLED的新颖概念，并且在各种光电子学中具有广泛应用的巨大潜力。