Device grade quantum dots (QDs) require QDs ensembles to retain their original superior optical properties as in solution. QDs with thick shells are proven effective in suppressing the inter‐dot interaction and preserving the emission properties for QDs solids. However, lattice strain–induced defects may form as the shell grows thicker, resulting in a notable photoluminescence quenching. Herein, a well‐type Cd_xZn_1−xS/CdSe/Cd_yZn_1−yS QDs is proposed, where ternary alloys CdZnS are adopted to match the lattice parameter of intermediate CdSe by separately adjusting the x and y parameters. The resultant thick‐shell Cd_0.5Zn_0.5S/CdSe/Cd_0.73Zn_0.27S QDs reveal nonblinking properties with a high PL QY of 99% in solution and 87% in film. The optimized quantum dot light‐emitting diodes (QLEDs) exhibit a luminance of 31547.5 cd m⁻² at the external quantum efficiency maximum of 21.2% under a bias of 4.0 V. The shell thickness shows great impact on the degradation of the devices. The T₅₀ lifetime of the QLEDs with 11.2 nm QDs reaches 251 493 h, which is much higher than that of 6.5 and 8.4 nm QDs counterparts. The performances of the well‐type thick‐shell QLEDs are comparable to state‐of‐the‐art devices, suggesting that this type of QDs is a promising candidate for efficient optoelectronic devices.

中文翻译：

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基于阱型厚壳CdxZn1-xS / CdSe / CdyZn1-yS量子点的高效量子点发光二极管

器件级量子点（QD）要求QD集成以保持其原始的优异光学特性（如溶液中一样）。已证明具有厚壳的量子点可有效抑制点间相互作用并保持量子点固体的发射特性。但是，随着壳的厚度增加，晶格应变引起的缺陷可能会形成，从而导致显着的光致发光猝灭。本文提出了一种井型的Cd _x Zn _{1- x} S / CdSe / Cd _y Zn _{1- y} S QDs，采用三元合金CdZnS通过分别调整x和y参数来匹配中间CdSe的晶格参数。生成的厚壳Cd _0.5 Zn_0.5 S / CdSe / Cd _0.73 Zn _0.27 S QD显示出非闪烁特性，溶液中的PL QY较高，膜中的Q QY值为99％。经过优化的量子点发光二极管（QLED）在4.0 V的偏压下，在最大外部量子效率为21.2％时，亮度为31547.5 cd m ^-2。壳的厚度对器件的性能下降有很大影响。具有11.2 nm QD的QLED的T ₅₀寿命达到251493 h，远高于6.5和8.4 nm QD的QLED。良好类型的厚壳QLED的性能可与最先进的设备相媲美，这表明这种类型的QD是高效光电器件的有希望的候选者。