Surface treatment on polyethylenimine interlayer to improve inverted OLED performance

Polyethylenimine(PEI) interlayer rinsing with different solvents for inverted organic light emitting diodes(OLEDs)is systematically studied in this paper. In comparison with the pristine one, the maximum current efficiency(CE_(max)) and power efficiency(PE_(max)) are enhanced by 21% and 22% for the device rinsing by ethylene glycol monomethyl ether(EEA).Little effect is found on the work function of the PEI interlayer rinsed by deionized water(DI), ethanol(EtOH), and EEA.On the other hand, the surface morphologies of PEI through different solvent treatments are quite different. Our results indicates that the surface morphology is the key to improving the device performance for IOLED as the work function of PEI keeps stable.     

溶液法制备基于新型热交联主体材料OLED器件的研究

为了得到溶液法制备的高性能的OLED器件,基于咔唑和1,2,4-三氮唑基团及可热交联的苯乙烯基团,设计并合成了可热交联的主体材料VB-CzTAZ。测试结果表明,VB-CzTAZ具有很好的热稳定性(Td:323℃),把该材料溶于氯苯旋涂成膜,该膜在手套箱中190℃下发生热交联。不同溶剂的薄膜清洗实验表明,热交联后的VB-CzTAZ具有优秀的抗溶剂性。基于VB-CzTAZ溶液法制备的绿光磷光器件,最低启动电压为5.1 V,最大亮度为2 404 cd/m~2,最大电流效率为4.3 cd/A,表明该交联材料可以用于溶液法制备多层OLED器件。