Colloidal ZnO nanoparticles (NPs) are widely used as an electron-transporting layer (ETL) in the solution-processed quantum-dot light-emitting diodes (QD-LEDs). However, the inherent drawbacks including surface defect sites and unbalanced charge injection prevent the device from realizing their further performance enhancement. In this work, a series of Mg doped ZnO (ZnO:Mg) and chloride-passivated ZnO ([email protected]) NPs were synthesized by using a solution-precipitation strategy, and they exhibited tunable optical bandgaps and upward-shift of conduction-band maximum (CBM). Solution-processed QD-LEDs based on cadmium-free Cu-In-Zn-S/ZnS (CIZS/ZnS) nanocrystals (NCs) were fabricated by using ZnO:Mg and [email protected] NPs as the ETLs, whose maximum peak external quantum efficiency (EQE) was nearly twice as high as that of QD-LEDs using ZnO NPs as the ETL (EQE = 1.54%). To take advantage of the benefits of ZnO:Mg and [email protected] NPs, [email protected]:Mg NPs were developed through the integration of Mg doping and Cl-passivation. Surprisingly, the cadmium-free QD-LEDs with the [email protected]:Mg NPs as the ETL exhibited a maximum peak EQE of 3.72% and current efficiency of 11.08 cd A^–1, which could be enhanced to be 4.05% and 12.17 cd A^–1 by optimizing the Cl amount, respectively. The positive effects of the Mg doping and Cl-passivation on the cadmium-free QD-LEDs are primarily ascribed to the reduced electron injection barrier of ETL/the emitting layer interface and slower electron mobility, which can be verified by the ultraviolet photoelectron spectroscopy (UPS) measurements and current density–voltage characteristics of electron-only devices.

中文翻译：

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氯化物钝化的Mg掺杂的ZnO纳米粒子，用于改善无镉，量子点发光二极管的性能。

胶体ZnO纳米颗粒（NPs）在溶液处理的量子点发光二极管（QD-LED）中被广泛用作电子传输层（ETL）。然而，包括表面缺陷部位和不平衡电荷注入在内的固有缺陷使该器件无法实现其进一步的性能增强。在这项工作中，使用溶液沉淀策略合成了一系列掺Mg的ZnO（ZnO：Mg）和氯化物钝化的ZnO（[受电子邮件保护]）NP，它们具有可调的光学带隙和导电性的向上偏移。最大频带（CBM）。以ZnO：Mg和[电子邮件保护] NP作为ETL，制造了基于无镉Cu-In-Zn-S / ZnS（CIZS / ZnS）纳米晶体（NC）的溶液处理QD-LED，其最大峰值外部量子效率（EQE）几乎是使用ZnO NPs作为ETL的QD-LED的两倍（EQE = 1.54％）。为了利用ZnO：Mg和[受电子邮件保护的] NP的优势，通过整合Mg掺杂和Cl钝化技术开发了[受电子邮件保护的]：Mg NP。令人惊讶的是，以[电子邮件保护]：Mg NP作为ETL的无镉QD-LED的最大峰值EQE为3.72％，电流效率为11.08 cd A^–1，通过优化Cl的量可以分别提高到4.05％和12.17 cd A ^–1。Mg掺杂和Cl钝化对无镉QD-LED的积极影响主要归因于ETL /发射层界面的电子注入势垒减小和电子迁移率较慢，这可以通过紫外光电子光谱法验证（ UPS）测量和纯电子设备的电流密度-电压特性。