Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang 330063, PR China; School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang 330063, PR China.
J Colloid Interface Sci. 2018 Jan 15;510:376-383. doi: 10.1016/j.jcis.2017.09.080. Epub 2017 Sep 22.
Type-II quantum dots (QDs) are emerging as a promising candidate for full color light sources owing to their advantages in achieving full color light by tuning the heterostructures. Despite the recent developments in type-II QDs, the choices of proper materials are limited for the composition of a high-quality QD and it still remains a big challenge to enhance the photoluminescence (PL) quantum yields (QYs) of type-II QDs for light-emitting diode (LED) applications. Here, we develop CdZnS/ZnSe/ZnS type-II QDs with a maximum quantum yield as high as 88.5%. Time-resolved PL results show that the ZnS shell suppresses non-radiative pathways by passivating the surface of CdZnS/ZnSe, thus leading to a high QY. Moreover, our results demonstrate that the outer ZnS also benefits the charge injection and radiative recombinations of the CdZnS/ZnSe. The LED based on green CdZnS/ZnSe/ZnS QDs achieves a current efficiency (CE) of 9.17cdA, an external quantum efficiency (EQE) of 8.78% and a low turn-on voltage of ∼2.3V.
II 型量子点（QDs）由于其通过调谐异质结构实现全色光的优势，正成为全色光源的有前途的候选者。尽管 II 型 QDs 最近取得了发展，但对于高质量 QD 的组成，合适材料的选择仍然有限，并且仍然是提高用于发光二极管（LED）应用的 II 型 QD 的光致发光（PL）量子产率（QY）的一大挑战。在这里，我们开发了 CdZnS/ZnSe/ZnS 型 II 型 QD，其最大量子产率高达 88.5%。时间分辨 PL 结果表明，ZnS 壳通过钝化 CdZnS/ZnSe 的表面来抑制非辐射途径，从而导致高 QY。此外，我们的结果表明，外层 ZnS 还有助于 CdZnS/ZnSe 的电荷注入和辐射复合。基于绿色 CdZnS/ZnSe/ZnS QD 的 LED 实现了 9.17cdA 的电流效率（CE）、8.78%的外量子效率（EQE）和低的开启电压约 2.3V。
