Study and improvement of the luminescent and degradation mechanism of organic electroluminescent devices

采用真空蒸发法制备了ITO/TPD/Alq 3/Mg结构的有机电致发光器件，并对其电致发光性能进行了研究。电致发光器件发射出强烈的绿色光，ITO电极的极性穿过TPD，穿透Alq 3并在那里与从Mg电极注入的电子复合，到达TPD/Alq 3界面区。光通过电子空穴材料发射。获得蓝色、绿色和红色光。本文研究了薄膜制备条件对有机电致发光器件性能的影响。主要研究结果如下：（1）Alq 3的高沉积速率导致高EL。(2)沉积速率对电致发光强度没有影响。(3)电子束蒸发提供了比RF溅射更好的ITO阳极。(4)具有低功函数的Mg导致高EL。(5)ITO衬底上的等离子体修饰降低了EL器件的驱动电压。(6)DCM和香豆素的掺杂给予EL器件高效率。(7)方酸菁染料的掺杂是一种新型的电致发光器件。优化有机电致发光薄膜的制备条件和材料的选择对提高有机电致发光器件的性能具有重要意义。

Organic EL devices with a structure of ITO/TPD/Alq3/Mg were prepared by the vacuumevaporation method and their EL properties were investigated in order to improve them. The EL device emits strong green light with the polarity of the ITO electrode move through TPD,penetrate into Alq3 and recombine there with electrons which are injected from Mg electrode and arrive at the TPD/Alq3 interface region. Light is emitted through the electron-hole materials. Blue,green and red lights are obtained. In this report, we have investigated the effects of the conditions of film preparation on properties of the organic EL device. Main results obtained are as follows; (1) High deposition rate of Alq3 resulted in high EL. (2) The deposition rate of TPD did not affect the EL intensity. (3) Electron beam evaporation provided a better ITO anode than RF sputtering. (4) Mg which has a low work function resulted in high EL. (5) Plasmamodification on the ITO substrate lowers the driven voltage of EL devices. (6) Doping of DCM and Coumarine gives EL device a high efficiency. (7) Doping of squarylium dye has a new type EL device. It is important for the improvement of the organic EL devices to optimize the conditions of film preparation as well as to select materials.