采用共混提高溶液法空穴传输材料的注入性能

Injection Property of Solution-Processed Hole Transport Materials Improved by Blending

研究了多种常用的基于溶液法的空穴传输材料,发现在空气中退火可以提高其空穴传输能力,性能接近蒸镀法制备的材料。但是这些材料很容易被发光材料的溶剂溶解,这限制了其在溶液法有机发光二极管(OLED)中的应用。为了提高空穴传输材料成膜后的抗溶解性能,将4,4′,4″-三(咔唑-9-基)三苯胺(TCTA)与聚(9,9-二辛基芴-CO-N-(4-丁基苯基)二苯胺)(TFB)共混,得到的混合空穴传输层退火后很难溶于常见的有机溶剂,而且具有优良的空穴传输性能。该共混材料作为空穴传输层应用于红色磷光器件中,最大电流效率达到11.2 cd/A,并且这层空穴传输层降低了发光层中极化子与三重态激子的淬熄,使器件具有非常低的效率滚降。

The multiple solution-processed hole transport materials were investigated.The hole transport abilities of solution-processed materials can be enhanced by annealing in the air,and the performances are comparable to those of the corresponding evaporated materials.However,those materials are easy to be dissolved by the solvents of emitting materials,which limits the application in solution-processed organic lighting-emitting diodes（OLEDs）.To improve the anti-solubility of the hole transport layer,the 4,4′,4″,-tri（N-carbazolyl）triphenylamine（TCTA）and poly（9,9-di-n-octylfluorene-alt-（1,4-phenylene-（（4-sec-butylphenyl）imino）-1,4-phenylene）（TFB）were blent.The fabricated mixing hole transport layer is hardly dissolved in common solvents after annealing,and has a good hole transport property.With the blending material as a hole transport layer in a red phosphorescent device,the maximum current efficiency is up to11.2 cd/A,and the device has a very low efficiency roll-off caused by the decrease quenching of the polaron and triplet exciton due to the hole transport layer.