Mixed halide CsPb(Br/Cl)₃ quantum dots (QDs) exhibit fine tunable blue light and narrow photoluminescence full-width at half-maximum (FWHM), which has attracted significant attention as a promising candidate to realize a new generation of blue light technology. However, the introduction of Cl⁻ makes it very easy to be eroded by water in the environment, which will lead to deep-level defects and degrade the luminescence and stability of QDs. Here, we propose to introduce tetra-n-octylammonium oxalate (TOAOxa) to improve the water-resistance stability and exciton recombination of CsPb(Br/Cl)₃ QDs and QD based light-emitting diodes (QLEDs). The oxalate ion (Oxa²⁻) of TOAOxa could form strong interaction with undercoordinated Pb²⁺ on CsPb(Br/Cl)₃ QD surface, which was confirmed by FTIR and XPS analysis. Oxa²⁻ passivated QDs (Oxa-QDs) exhibited improved photoluminescence quantum yield (PLQY) and enhanced water-resistance stability compared to pristine QDs. For example, after soaking in water–acetone co-solvent for 1 h, Oxa-QDs can maintain the initial cubic morphology and 43.9% of initial PL intensity, while the morphology and luminescence of pristine QDs are almost damaged. Based on the above concept, the Oxa-QD-based QLED presented a maximum external quantum efficiency (EQE) of 4.0%, and operational lifetime (T₅₀) of 84 s, which was a 5-fold enhancement in EQE, and 7-fold enhancement in stability compared to pristine QLED, respectively. Besides, the Oxa-QD-based QLED exhibits better stability in high-humidity air. To sum up, the Oxa²⁻ passivation strategy has significantly improved the efficiency and water-resistant stability of QDs and devices and would rapidly promote the development of blue-emitting QDs.

混合卤化物CsPb(Br/Cl) ₃量子点（QD）表现出精细可调的蓝光和窄光致发光半峰全宽（FWHM），作为实现新一代蓝光的有希望的候选者而受到广泛关注技术。^{然而， Cl−}的引入使其很容易被环境中的水侵蚀，从而导致深能级缺陷，降低量子点的发光和稳定性。在这里，我们建议引入四正辛基草酸铵（TOAOxa）来提高CsPb（Br/Cl） ₃ QD和基于QD的发光二极管（QLED）的耐水稳定性和激子复合。草酸根离子 (Oxa ²⁻TOAOxa ) 可以与CsPb(Br/Cl) _{3 QD 表面上的欠配位 Pb} ²⁺形成强相互作用，这一点通过 FTIR 和 XPS 分析得到证实。与原始量子点相比， Oxa ²⁻钝化量子点（Oxa-QD）表现出更高的光致发光量子产率（PLQY）和增强的耐水稳定性。例如，在水-丙酮共溶剂中浸泡1小时后，Oxa-QDs可以保持初始的立方形貌和初始PL强度的43.9%，而原始QDs的形貌和发光几乎被破坏。基于上述概念，基于Oxa-QD的QLED呈现出4.0%的最大外量子效率（EQE）和工作寿命（T ₅₀) 84 秒，与原始 QLED 相比，EQE 提高了 5 倍，稳定性提高了 7 倍。此外，基于Oxa-QD的QLED在高湿度空气中表现出更好的稳定性。综上所述，Oxa ²⁻钝化策略显着提高了量子点和器件的效率和耐水稳定性，将迅速推动蓝光量子点的发展。