Development of nano-electroluminescent devices by self-organization

该研究项目的目的是形成高发射的微图案化有机发光二极管。微图案的制造方法是通过稀溶液的去湿机制自组织空穴传输材料的微尺寸液滴。利用微图形控制有机导体的取向，从而提高微图形的发光性能，得到以下结果：1.稀溶液浇铸导致无定形微液滴的形成。热退火导致有机材料的结晶。晶体形态可以通过退火温度和预退火超声处理步骤来控制。2.通过对电荷注入层进行低功函数金属或配合物的包覆，可以改善电荷注入层的性能; 3.新合成的芳胺或三嗪衍生物可以分别作为空穴导体和电子导体。其中一些化合物在热退火时也形成了取向的微晶。4.通过使用高热导率的衬底和将电极尺寸减小到几μ m，可以获得超过10，000 A/cm^2的极高电荷密度。5.通过去湿法对空穴导体进行微图案化，并通过真空沉积电子导体和顶部电极来制备OLED。使用光学显微镜来显示仅去湿的空穴导体发光。因此，可以制备微米尺寸的发光点。去湿空穴导体的退火导致形成显示发光增加4倍的微米级盘状聚集体。

The aim of the research project was the formation of highly emitting micropatterned organic light emitting diodes. The fabrication method for the micropatterns was the self-organization of micro-sized droplets of hole transport materials via a dewetting mechanism from dilute solution. The micropatterns were used to control the orientation of the organic conductors and thus increasing the luminescence of the micropatterns.The following results were obtained :1.casting from dilute solution led to the formation of amorphous microdroplets. Thermal annealing led to the crystallization of the organic material. Crystal morphology could be controlled by the annealing temperatare and by a pre-annealing ultrasonication step. Single crystal, polycrystrals as well as crystal fibers could be prepared.2.The charge injection layer could be improved by coating with low work function metals or complexes.3.Newly synthesized arylamines or triazine derivatives could be used as hole and electron conductors, respectively. Some of those compounds also formed oriented microcrystals upon thermal annealing.4.Extremely high charge densities of more than 10,000 A/cm^2 could be obtained by using substrates with high thermal conductivity and by reducing the electrode size to a few μm.5.Hole conductors were micropatterned via dewetting, and OLEDs were produced by vacuum deposition of electron conductors and top electrodes. Optical microscopy was used to show that only the dewetted hole conductors emitted light. Thus micronsized light emitting spots could be prepared. Annealing of the dewetted hole conductors led to the formation of micronsized disk-shaped aggregates that showed a 4 fold increase in luminescence.