Electron‐transporting layers (ETLs) assembled from SnO2 nanocrystals show promise in addressing the stability issues faced by solution‐processed quantum dot light‐emitting diodes (QLEDs). However, the electrical conductivity of SnO2 nanocrystals bottlenecks QLED performance, and efforts to achieve effective n‐type doping are constrained by dopant availability and charge‐induced exciton quenching. In response, Sb‐doped SnO2 nanocrystals with doping concentrations less than 1 mol% are explored, a range overlooked in previous research, and the ETL is designed accordingly. Comprehensive characterizations reveal that 0.45 mol% Sb doping transitions the electrical conduction from trap‐limited to trap‐free space‐charge‐limited, and 0.84 mol% doping results in Ohmic conduction, along with a 100‐fold conductivity enhancement. Meanwhile, trap‐filling mitigates the fluorescence quenching of the colloidal quantum dots, with significant increases only observed when doping concentrations exceed 0.45 mol%. Drawing inspiration from these findings, a SnO2 ETL with gradient Sb doping levels for QLEDs to decouple the conductivity–fluorescence tradeoff is developed. Consequently, this ZnO‐free QLED significantly outperforms comparable devices, achieving a luminance of 2.8 × 105 cd m−2, an external quantum efficiency of 18.3%, and a T95 operational lifetime of 4320 h at 1000 cd m−2, all while showing no signs of positive aging.

中文翻译：

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解耦 SnO2 纳米晶体的电导率-荧光权衡，实现高效稳定的量子点发光二极管


由 SnO2 纳米晶体组装的电子传输层 （ETL） 有望解决溶液处理量子点发光二极管 （QLED） 面临的稳定性问题。然而，SnO2 纳米晶体的导电性阻碍了 QLED 性能，并且实现有效 n 型掺杂的努力受到掺杂剂可用性和电荷诱导激子淬灭的限制。作为回应，探索了掺杂浓度小于 1 mol% 的 Sb 掺杂 SnO2 纳米晶体，这是先前研究中忽略的范围，并相应地设计了 ETL。全面的表征表明，0.45 mol% Sb 掺杂使导电从陷阱限制转变为无陷阱空间电荷限制，而 0.84 mol% 掺杂导致欧姆传导，同时电导率提高了 100 倍。同时，陷阱填充减轻了胶体量子点的荧光猝灭，只有当掺杂浓度超过 0.45 mol% 时才能观察到显著增加。从这些发现中汲取灵感，开发了一种用于 QLED 的具有梯度 Sb 掺杂水平的 SnO2 ETL，以解耦电导率-荧光权衡。因此，这种不含 ZnO 的 QLED 明显优于同类器件，实现了 2.8 × 105 cd m-2 的亮度、18.3% 的外部量子效率和 4320 小时的 T95 工作寿命在 1000 cd m-2 下，同时没有显示出正老化的迹象。