聚酰亚胺型有机半导体发光材料及显示器件

Organic electroluminescent diodes (OLEDs) have attracted much interest because of their potential application for flat color displays driven at low voltage. In spite of their lifetime, driving voltage, efficiency, brightness, and chromaticity control have reached commercial requirement, lower reliability affect their practical use. In order to increase the reliability of OLEDs, many researches have been performed to improve the stability of organic materials and the interface between the metal electrode and organic thin film. Thermal stability is one of the most important requirements in OLEDs, because the Joule-heat generated during the device may relax and damage organic materials or metals. To obtain electroluminescent materials with high thermal stability, we designed and synthesized a new kind polyimide containing fluorescent dye in the backbone. By introducing large lateral group, 9,9'-diphenylfluorene, into the polymer backbone, the polyimide processed excellent solubility in low boiling solvents (such as chloroform, THF), good thermal stability (Td > 500 0C and Tg > 300 0C) and good film formability (film could be prepared by spin-coating polyimide solution on ITO surface). The polyimide emitted strong solid photoluminescence because the fluorescent dye content is low by introducing the second dianhydride or diamine to form copolyimide to dilute dye content in the polyimide. By using fluorescent polyimide as luminescent materials, single- and double-layer devices were prepared. The devices showed rectifying characteristic under forward bias, turn-on voltage is about 12 V and emitted yellow-green light. Six series of poly(p-phenyleneethynylene)s (PPEs) derivatives have been prepared by Heck or phase transfer reaction. By introduced different alkyloxy groups (such as -OCH3, -OC8H17, -OC12H23 ) into the aromatic rings, the solubility of these polymers can be significantly improved. By using different PPEs as luminescent materials, red-, blue- or green- electroluminescent diodes were successfully prepared. A series of novel electroluminescent polymers (Cn) containing hole- and electron-transporting units have been prepared by free radical copolymerization. Some single layer light-emitting diodes based on Cn were fabricated. Under forward bias, the devices emitted red (Cn containing europium complex) or green (Cn containing terbium complex). Total 15 articles (SCI) concerned on above research results have been published (or accepted).

设计合成一类含聚酰亚胺结构，电子、空穴传输结构，发光波长可调的新一类聚酰亚胺主链结构型有机半导体电致发光材料。采用类金刚石薄膜等低逸出功材料作器件阴极。研究电致发光器件构造对电致发光波长、量子效率、稳定性影响的规律性。优化材料结构和器件构造。这是一项崭新、多学科交叉的前沿研究。