采用光学干涉方法实现高对比度聚合物发光二极管

High Contrast Polymer Light Emitting Diode With Destructive Light Interference Layers

为了得到高对比度的聚合物发光二极管(PLED),设计并制作了消光干涉结构位于有机层之外的新型聚合物二极管。消光干涉层的结构为:CrOx/Cr/ITO/Cr。在玻璃衬底和ITO阳极之间溅射的光学干涉层可以部分消去背景光的反射。这种方法不需要考虑光学干涉层和OLED或PLED材料之间功函数匹配,以及在溅射过程中对有机层的损伤等问题。制作的器件的对比度为14.7∶1,这比没有采用光学干涉结构的器件的对比度要高得多。结果说明新型的光学干涉结构确实起到了提高器件对比度的效果,对器件参数的进一步优化有望达到一个实用化目标。

In order to get higher contrast for polymer light emitting diode（PLED）, a novel optical interference structure outside the PLED functional layers is designed. The destructive light interference layers are CrOx/Cr/ITO/Cr. The optical interference layers are deposited between the glass substrate and ITO（indium tin oxide） anode, which could partly suppress the reflection of ambient light. The match of work functions of the light interference materials with those of OLED or PLED materials and the damages by sputtering deposition are avoided. The contrast ratio obtained so far is 14.7： 1, which is higher than that of the device with normal structure. The result indicates that the reflection of the ambient light is suppressed by the light interference layers. Further optimization is needed to reach an applicable value.