高发光亮度高效率的异质结聚合物电致发光器件

High Luminescent Brightness and Efficiency Electroluminescent Devices Based on Heterojunction

成功制备了可溶性的空穴型聚合物 PDDOPV [poly （2,5-bis （dodecyloxy）-phenylenevinylene）]与电子型聚合物 PPQ [poly（phenyl quinoxaline）]构成的异质结有机薄膜发光二极管。异质结器件的最高亮度是其本身最低亮度的106倍,是 PDDOPV单层器件的 365倍,而最高效率则是 PDDOPV单层器件的 336倍。异质结器件在正向、反向以及交流驱动下均可获得发光,但在正向和交流驱动下的发光来自PDDOPV,而反向驱动下的发光既有来自 PDDOPV的,也有来自 PPQ的。反向偏压下器件获得发光的原因是高场强使得能带高度倾斜,高度倾斜的结果使得载流子的注入势垒变得足够薄从而被载流子隧穿,从而导致载流子的注入和复合。

An organic light-emitting diode based on heterojunction consists of hole-type polymer PDDOPV [poly (2,5-bis (dodecyloxy)-phenylenevinylene)] and electron-type PPQ [poly (phenyl quinoxaline)] is successfully fabricated. The highest brightness of the heterojunction device is 106 times of the lowest brightness of its own, 365 times of that of single layer device of PDDOPV. The highest luminescent efficiency is 336 times of that of single layer device of PDDOPV. The heterojunction devices can be operated at forward bias voltage, reverse bias voltage and ac (alternating current) voltage. Emission at forward bias voltage and ac voltage are from PDDOPV, but emission at reverse bias voltage includes not only emission from PDDOPV but also emission from PPQ. The reason of the capability of heterojunction device can be operated at reverse bias voltage is that enough high electric field leads to the tilt of energy band, then the tilt of energy band makes the injection barrier thin enough to be injected by carriers through tunnel.