藍光有機發光元件之光電性質量測

Abstract

在本篇論文中，我們將對藍光有機發光元件 (OLED) 的光電性質做量測與討論。量測的內容包括發光亮度、頻譜、色度座標及視角，以及元件操作的電流-電壓 (I-V) 特性、壽命時間，和有機材料的載子移動率。首先，我們對一組高效率的異質接面 (hetero-junction) 藍光有機發光元件做光電性質量測，其在100 mA/cm2的電流密度驅動下，可獲得 13 cd/A 的高電流效率。同時，藉由元件的暫態發光特性 (TREL) ，可以得到有機材料的載子移動率。然而，這樣的元件雖然有著高效率的結果，但卻有操作壽命不足的缺點。為了改善這個缺點，我們利用有機混合層 (Mixing-Layer) 的方法，延長其操作壽命至原先元件壽命之六倍，同時亦可同時降低其驅動電壓。為了更進一步加強元件的外部量子效率 (EQE)，我們在元件基版的玻璃面貼上各種薄膜，以減少玻璃與空氣介面全反射情形的發生，進而達到增強外部量子效率的結果。在本實驗中，最高外部量子效率已經達到 11.0 %。

In this thesis, we demonstrated the measurement results of electrical and optical characteristics of blue organic light-emitting devices (OLED). The measurements include the brightness, spectrum, CIE coordinate, view angle, current-voltage (I-V) characteristic and operation lifetime of the device, and also the carrier mobility of the organic thin films. First we measured the device performances of a high efficiency hetero-junction blue OLED which has a high current efficiency of 13 cd/A under the current density driving at 100 mA/cm2. Then we obtained carrier mobility of the organic thin films by the transient electroluminescence (TREL) measurement. However, the operation lifetime is still not long enough. To improve, we use mixing-layer technology which can extend the operation lifetime by six times, along with the lower driving voltage. To increase the external quantum efficiency (EQE), we used different film attachments on the devices substrate to reduce the total internal reflection (TIR) effect between glass/air. An OLED with the EQE of 11.0 % is demonstrated.