基于高质量InP核壳结构量子点的高性能电致发光器件

InP-based quantum dot light emitting devices (QLED) are considered as promising light sources for the next generation solid-state lighting and displays, due to possessing not only advantages of traditional QLED but also the heavy metal-free (Cd,Pb etc.) characteristics. The low luminance efficiency and brightness of InP-based QLED are the major obstacles for their practical applications of InP-based QLED. The improvement of the luminance efficiency and stability of InP quantum dot (QD) thin film and the building of QLED with matching energy levels and balanced carrier injection efficiency between the QD layer and other functional layers are the key scientific issues needed to be resolved towards the realization of InP-based QLED with high efficiency and high brightness. Based on this, this project, by precise controlling the kinds of cores, composition and thickness of the shell materials will be carried out to improve the uniformity and quantum yield of InP-based core-shell QDs, also including the fabrication of InP-based QD films with high quantum yield of more than 70% with QDs protected by the substitution ligands of short-chain ones. Lastly, Carrier transport layer design will be introduced in the InP-based QLED to construct new device structure, which can effectively improve the injections balance of carriers and the energy level matching of layers in QLED and finally achieved the InP-based QLED with high efficiency and high brightness.

InP基量子点发光二极管（QLED）不仅具有传统II-VI族QLED的优点，更因其不含毒性重金属（Cd、Pb等）的特点有望在下一代固态发光和平板显示技术中得到广泛应用。当前InP基QLED进入实际应用的主要障碍是发光效率和亮度显著偏低。因此如何进一步提高InP基发光层量子点薄膜的发光效率，以及构建能级匹配和载流子注入平衡的器件结构，是解决InP基QLED性能低下的关键因素，也是目前亟待解决的关键科学问题。基于此，本项目拟通过精确控制InP基核壳结构量子点壳层材料的种类、组分、厚度，提高其粒径尺寸、均一性及其量子产率；进一步通过对其表面长链配体的取代实现短链配体修饰，研制量子产率70%以上的量子点薄膜；同时通过壳层的优化实现器件中各功能层之间的能级匹配，提高其电光效率；通过对载流子传输层再设计，构建新器件结构，提高载流子注入平衡，最终实现高效率、高亮度的InP基QLED。

四年来围绕项目开展了系列卓有成效的工作，发展了系列量子产率大于90%的量子点可控制备新技术；建立了界面修饰提升量子点发光层电荷传输能力的新策略，大幅提升了蓝色QLED的效率和寿命；构建了发光层能级适配传输层的新体系，显著提升了空穴注入效率，研发了兼具高亮度、高效率和长寿命的QLED器件，创下了三基色QLED器件效率、亮度、寿命多项国际纪录；提出了原位刻蚀提升InP基核壳结构量子点发光性能的新思路，并构筑了目前效率、寿命、亮度最高的InP基红色QLED。项目执行期间在Nat. Photonics（1篇）、Nano Lett.（4篇）、Adv. Funct. Mater.（3篇）等期刊发表SCI论文24篇，其中影响因子大于10的12篇。论文多次被Chem. Rev.、Chem. Soc. Rev.、Nat. Electron.、Adv. Mater.等期刊图文引用和重点评述，四年SCI他引2000余次。申请发明专利11项，授权7项（其中PCT专利一项），技术转让3项。培养博士生3人，硕士毕业生21人。成果入选中国光学十大进展，获河南省自然科学二等奖一项（排名第一），并被国家自然科学基金委作为2020年首期简报上报中央办公厅、全国人大办公厅、国务院办公厅等重要国家领导部门。