基于量子点下转换层的高性能顶发射白光有机发光器件研究

Compared to the traditional bottom-emitting device, top-emitting white organic light-emitting devices (TEWOLED ) can be deposited onto arbitrary substrates, which has unique advantages in high-aperture-ratio displays and lighting. The yield and lifetime are the main problems in weak microcavity TEWOLED with thin metal cathode, and strong microcavity TEWOLED has the problem in efficiency and spectral angle stability. Besides, the spectra time stability is bad in the RGB multi-emissive layer devices. In 2008, we had reported the TEWOLED with down-conversion layer, the spectra-time-stability and yield problems can be resolved, but the spectral angle stability and efficiency need to be improved. This project proposes to study TEWOLED with quantum dots down conversion layer. The quantum dots have broad excitation spectrum and high quantum efficiency. Combined with high performance blue top-emitting OLED, we can solve efficiency, spectral time and angle stability problem on TEWOLED. The research contents of this project are as follows: (1) high-performance organic light-emitting materials and non-toxic quantum dots suitable for down-conversion TEWOLED; (2) high efficiency blue top-emitting OLED with stable spectral angle characteristics; (3)integrated technology for non-toxic efficient quantum dots down conversion layer and top emitting blue OLED.

相比传统底发射白光器件，顶发射白光有机发光器件(TEWOLED)可制备于任意衬底，在高开口率有机显示和照明上有独特优势。当前采用超薄金属为阴极的弱微腔TEWOLED存在成品率和寿命问题，而强微腔TEWOLED存在光谱角度稳定性和效率问题，且采用红绿蓝多发光层的器件还存在光谱时间稳定性问题。本课题组2008年首次实现了下转换型TEWOLED，可解决TEWOLED光谱的时间稳定性和成品率问题，但器件的光谱角度稳定性和效率有待提高。本项目提出进行基于量子点下转换层的TEWOLED研究，利用量子点宽激发谱、高量子效率的特点，结合高性能蓝光顶发射OLED，解决TEWOLED的效率问题及光谱的时间和角度稳定性问题，国际上未见相关报导。研究适用于TEWOLED的高性能有机光电材料和无毒高效量子点材料、光谱角度特性稳定的顶发射蓝光OLED及二者的集成技术，为OLED照明和显示器件的发展提供行之有效的方法。

本项目主要进行基于量子点下转换层的顶发射白光有机发光器件的研究，按照研究计划开展了相关的研究工作，取得了如下研究成果：(1)将高效顶发射蓝光器件与微结构量子点下转换膜结合，制备出了具有较强光谱角度稳定性的顶发射白光器件，研究了微结构对器件性能的影响；(2)通过将底发射蓝光OLED、微结构量子点下转换膜与彩色滤光片结合，制得了颜色稳定的白光、红光、绿光和蓝光(WRGB)OLED；(3)合成了一种新型的双极性材料EBBPC，基于该材料为主体的红、绿、蓝光器件的最大外量子效率分别为14.9 %、15.6 %和16.0 %；(4)在基于CBP为主体，FIrpic为客体的蓝色磷光OLED发光层内引入激子控制层对器件的载流子进行调控，器件外量子效率提高了53.8%；(5)设计一种HOMO能级高于FIrpic的主体材料p2PCB2CZ，基于该主体的蓝色磷光OLED最大EQE可达19.6%。本项目共发表学术论文20篇，其中影响因子大于3的SCI检索论文12篇，申请发明专利3项，其中一项已授权；参加国内学术会议5人次；培养博士研究生1人，硕士研究生4人。