低驅動電壓長壽命有機電激發光二極體

Abstract

目前在藍光有機電激發光二極體驅動電壓高且色純度不佳是一直無法解決的問題. 本論文針對此問題提出兩個方式以解決上述問題： 1.多層電洞注入傳輸結構:電洞注入層及電洞傳輸層的膜厚元件影響內部的載子行為，進而產生元件內部的光學干擾，稱為微共振腔效應(micro-cavity effect)，在有機發光二極體中，不論在上發光或是下發光元件都有程度不一的共振腔效應。微共振腔效應主要是指不同能態的光子密度被重新分配，使得只有特定波長的光波段在符合共振腔模式後，得以在特定的角度射出，因此波長半高寬(FWHM)也會變窄，在不同角度的強度與光波波長也會不一樣，藉此可改善色純度不佳問題。 2.電子傳輸層共蒸鍍:目前已經有許多文獻記載，利用共蒸鍍法製備電子傳輸層可以降低電子注入能障界面，使電子注入傳輸更為順暢．利用以上兩種方法（多層電洞注入傳輸結構及電子傳輸層共蒸鍍）可達成電子電洞平衡,加上元件結構蒸鍍速度不同及陰極元件結構可達成低驅動電壓長壽命有機電激發光二極體藍光元件結構。

High driving voltage and poor chromaticity remain two serious problems in blue organic light-emitting diodes (OLED) In this study, we develop two methods to solve the problems： 1. The thickness of HIL and HTL will affect the micro-cavity effect. No matter top emission or bottom emission OLED have micro-cavity effect, which means the photon density in different states would be redistributed. After resonance, a specific wavelength wave can be emitted in a specific angle and the full width at half maximum (FWHM) of the wave will be narrower. 2. Electron-transport layer (ETL) by co-evaporation: It has been shown in literature that ETL by co-evaporation can effectively lower the electron injection barrier. Combining method 1 and 2, as well as different rate deposition and cathode deposition, it will make electron and hole equivalent, resulting in low driving voltage and long life deep blue OLED.