Development of White-light-emitting Organic Electroluminescent Device

采用染料分散聚合物发射层和多层器件结构，研制了白光有机电致发光器件。在聚合物发射体层中，为了在单聚合物发射体层中实现双极性，将空穴输运聚（n-乙烯基咔唑）（PVK）与2-（4-联苯基）-5-（4-叔丁基苯基）-1,3,4-恶二唑等电子输运添加剂进行分子分散。此外，几种具有不同发射颜色的荧光染料分散在发射中心。通过调节荧光染料的浓度，获得了最大亮度为4100 cd/m^2的白光，这是迄今为止在有机电致发光器件中观测到的最亮的白光。在多层结构中，使用三个具有不同载流子输运特性的发射层，每个发射层发出蓝光、绿光或红光，来产生白光。成功地获得了超过2000 cd/m^2的明亮白光。我们还合成了含有三苯胺部分的空穴传输聚合物和蓝色荧光染料。

White light-emitting organic electroluminescent devices were developed by using dye-dispered polymer emitter layrs and by using a multilayr device structure. In case of the polymer emitter layr, in order to achieve bipolarity in the single polymer emitter layr, hole-transporting poly (N-vinylcarbazole) (PVK) was molecularly dispersed with electron-transporting additives such as 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole. In addition, several fluorescent dyes, having different emission colors, were dispersed aa emitting centers. By adjusting the concentration of the fluorescent dyes, white light with a maximum luminance of 4100 cd/m^2 was obtained, which is the brightest white light ever observed for organic electroluminescent devices. In case of the multilayr trpe, three emitter layrs with different carrier transport properties, each emitting blue, green or red light, are used to generate white light. Bright white light, over 2000 cd/m^2, was successfully obtained. We have also synthesized hole-transporting polymers containing triphenylamine moieties and blue-emitting fluorescent dyes for EL application.