Development of nano-electroluminescent devices by self-organization

该研究项目的目的是形成高发射微图案化有机发光二极管。微图形的制备方法是通过稀溶液的去湿机制自组织微尺寸的空穴传输材料液滴。利用微图形来控制有机导体的取向，从而提高微图形的发光。结果表明：1.从稀溶液中浇注导致了无定形微滴的形成。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步骤来控制。可以制备单晶、多晶以及晶体纤维。2.可以用低功函数金属或络合物包覆电荷注入层。3.新合成的芳胺或三氮杂衍生物可分别用作空穴导体和电子导体。4.采用高导热系数的衬底，将电极尺寸减小到几个μm。5.用去湿法制备孔导体微图案化，用真空沉积电子导体和顶电极制备有机电致发光器件。光学显微镜被用来显示只有去湿的孔导体发射光。因此，可以制备微米级的发光点。退湿后的空穴导体形成了微米级的盘状聚集体，其发光强度增加了4倍。

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.