基于原子层沉积技术的倒置顶发射有机发光器件及关键问题研究

Owing to the merits of large area, flexibility, low cost and fast response, organic light-emitting device (OLED) has been seen as next-generation full color flat panel display in future. Active matrix OLED (AMOLED) will be the mainstream trend of the development of OLED display technology, and for AMOLED with n-channel thin film transistor (TFT), inverted top-emitting OLED (TOLED) is easier integrated with underlying driving circuits with bottom cathode connected to the drain end of an n-channel TFT and provides higher aperture ratio and more device stability with longer lifetime. So the overall research objective of our proposal is to develop efficient inverted TOLED facing to the potential use in AMOLED. The main focus of the proposed research is the studies on the interfacial physics, the managements of the carriers and excitons, the optimization of thin film growth method of high performance transparent conducting oxide, modified layer and index-matching layer by atomic layer deposition (ALD) and other key scientific issues. We will carry out related research on the critical factors for the device performance. Problems which are to be studied include the selection of cathode and transparent anode and the effect of interfaces physics on the carrier injection efficiency, and the highly efficient device structure. The final objective is to obtain high performance inverted TOLED. Our research findings of this proposal will provide references for the fundamental researches and industrialization development of AMOLED in future.

有机电致发光器件(OLED)由于具有易于实现大面积柔性显示、成本低、响应速度快等优点，近年来被权威研究机构看好成为新一代平板显示技术。有源OLED显示(AMOLED)是未来OLED显示技术发展的主流方向，而对于基于n沟道薄膜晶体管的AMOLED，采用底电极为阴极的倒置顶发射OLED(TOLED)更易于与驱动电路集成，获得高开口率，实现稳定工作。本项目拟以倒置TOLED为研究目标，围绕界面物理及载流子、激子的动力学等关键科学问题，优化原子层沉积技术制备高性能透明导电氧化物、修饰层及增透膜的工艺，分别针对底阴极及透明阳极的选择与制备、界面物理、高性能器件结构等影响器件性能的关键因素开展相关研究，力争在倒置TOLED所涉及的制备工艺、关键物理与技术问题上有所突破，最终制备出综合性能较好的倒置TOLED。本项目的实施将会为AMOLED的基础研究与产业化进展提供参考。

有机电致发光器件(OLED)具有高效率，柔性，低成本和大面积的优点，在全色平板显示和固态照明领域具有巨大的应用价值，引起了国内外科研机构的广泛关注。对于基于n沟道薄膜晶体管的有源OLED显示,采用底电极为阴极的倒置顶发射OLEDs ( Inverted top-emitting OLEDs，ITOLEDs)更易于与驱动电路集成实现有源显示。为了提高ITOLEDs的性能，设计出高反射率的底阴极，优化载流子的注入与传输是非常必要的。本项目以ITOLED为研究目标，围绕界面物理及载流子、激子的动力学等关键科学问题，优化了原子层沉积技术制备高性能透明导电氧化物、修饰层及增透膜的工艺，分别针对底阴极及透明阳极的选择与制备、界面物理、高性能器件结构等影响器件性能的关键因素开展相关研究。具体研究内容及结果如下：（1）我们采用渐变掺杂结构制备出高性能的单层绿光OLEDs，最大功率效率和电流效率分别达到 44.8 lm/W and 42.7 cd/A。我们发现发光材料对单层OLEDs的载流子平衡和激子符合区域起到重要作用。（2）实现了色坐标为(0.156, 0.050)深蓝色荧光OLEDs。（3）成功制备出双层双母体结构白光OLEDs，最大功率效率为 71.9 lm/W（1000 cd/m2下的功率效率达到59.3 lm/W）。（4）制备了以Ag自掺杂Bphen为修饰层的ITOLEDs，该器件具有低开启电压，最大效率可达76.4 cd/A。本项目执行期间，共发表SCI论文25篇，授权5项国家发明专利。