基于石墨烯电极的高性能柔性有机发光二极管及力学性能研究

Organic light-emitting diode (OLED) has a potential application in full-color displays and lighting area because of many advantages, especially realizing flexibility. However, ITO, a widely used anode material, has some disadvantages such as crispness, franglibility when bending, rare raw material, a high cost, and so on. In this project, we use graphene as the electrode to replace ITO in flexible OLED, and develop some scientific research work on the fabrication of graphene with a low resistance, the transfer of graphene, and the patterned method of graphene. We will design and fabricate a flexible OLED based on graphene anode. Then, some methods including the reduced surface roughness, the improved interface performance of graphene electrode, and the device structure optimization will be utilized to maximize the optical and electrical performances of OLED. Furthermore, the effects of the strain of the adjacent layers including the flexible substrate and the surface energy of every layer on the mechanical performance in the OLED will be explored. The flexible OLED with excellent emission characteristics and a good mechanical strength will be successfully fabricated in our project by balancing the relation between the optical, electrical, and mechanical performances, which will promote the application of flexible OLEDs in full-color displays and lighting area.

有机发光二极管（OLED）在全彩显示和照明领域有着极广泛的应用前景，可实现柔性更是OLED区别于其它显示和照明技术的最大优势。针对常用于OLED阳极的ITO具有弯折易碎、原材料稀少、成本高等缺点，本项目拟开发石墨烯作为柔性OLED电极，围绕低阻石墨烯的简易制备、转移及图案化处理等问题展开科学研究，设计并研制出石墨烯作电极的柔性OLED，探索包括柔性基底平坦化、石墨烯电极的界面改善以及器件整体结构优化在内的器件性能优化方案，研究包含基底在内的OLED的层间应力及膜层表面能对于重复机械弯曲性能的影响，权衡发光性能与机械性能的制约关系，最终研制出发光性能优异同时机械性能良好的柔性OLED。本项目基于石墨烯电极的高性能柔性OLED的成功研制将为柔性OLED照明和显示的进一步实用化奠定基础。

柔韧性良好的石墨烯是一种极具应用价值的电极材料，在柔性有机发光器件(OLED)中有着重要的应用前景。本项目围绕高导电性石墨烯电极展开研究工作，从石墨烯的高效制备、转移及低阻化等科学问题入手，提出了冷壁低压反应器CVD制备技术，发展了O3等离子体辅助过硫酸铵腐蚀法，开发出了电化学鼓泡法转移石墨烯技术，制备出了导电性较好的石墨烯电极材料。在有机发光器件(OLED)应用方面，成功发展了多种石墨烯修饰技术（包括弱酸、空穴传输材料、金属卤化物等），开发出了一种简化器件制备工艺的软件，设计出了多种稳定高效的柔性OLED结构，通过构建石墨烯方阻、载流子注入、平衡输运与OLED器件性能间的内在关联，深入分析石墨烯OLED工作机理，制备出了高性能的石墨烯OLED器件，圆满地完成了预定的目标和任务。本项目提出的弱p型掺杂技术和梯度注入方法，在非级联的单结结构中实现了高达346.1 cd A-1 (135.9 lm W-1)的白光发射和199 cd A-1 (70 lm W-1)的蓝光发射，发光性能达到国际顶尖水平；研发出具有自主知识产权的柔性器件测试装置，正在与公司进行联合推广。本项目关于高性能石墨烯OLED方面的研究成果，同样可为石墨烯应用于其它光电器件（如有机光伏器件、钙钛矿发光器件、钙钛矿太阳电池）提供重要的借鉴。本项目取得的成果已陆续发表于Adv Mater、Appl Phys Lett、Adv Opt Mater、ACS Appl Mater Inter、Nanoscale、Org Electron、J Mater Chem C、J Appl Phys等国际重要期刊（部分成果投稿于Nat Photon和Nat Commun），共计发表SCI期刊论文37篇（IF>3.0 21篇），公开或授权中国发明专利7件（2件获授权），培养博士生1名、硕士生9名。