發光層之光學特性對有機發光元件效能之研究

Investigations of Optical Properties of Emitting Layers on Characteristics of Organic Light-Emitting Devices

李偉愷(Wei-Kai Lee)

指導教授 ： 吳忠幟

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.10053

摘要

近年來,有機發光元件已經快速發展成一具有潛力的平面顯示與照明技術,為 了滿足高效率、低操作電壓、長壽命的元件特性要求,必須設法了解元件的光學特 性,以達到最佳的外部出光效率,減少被侷限在元件內部的能量。
在本論文的第一部分,我們透過半古典電磁模型來建構一個模型來描述平面 層狀的有機發光元件之光學特性。首先,我們利用δ函數電流源來描述一個發光體 並利用馬克斯威爾方程式和轉移矩陣的方法推導出元件中的電磁波的行為及其能 量分布。此外,我們利用發光體的分佈函數來描述多個發光體的特性。最後我們結 合單個發光體的結果以及發光體的分佈函數來模擬平面層狀結構的有機發光元件 的光學特性。
在本論文的第二部分,我們討論如何從實驗的數據中萃取出發光材料的水平 電偶極矩之比例。接著我們討論水平電偶極矩的比例造成元件效率的影響。

關鍵字

有機發光元件,馬克斯威爾方程式,分佈函數,水平電偶極矩

並列摘要

Organic light-emitting devices (OLEDs) have been demonstrated as a potential display and lighting technology. In order to achieve high efficiency, low operating voltage and long operating lifetime, we should understand the optical characteristics in OLEDs in order to achieve the best external quantum efficiency (EQE) and to reduce the energy trapped in device.
In the first part of the thesis, we construct a semi-classical electromagnetic model for simulating optical properties of planar layered OLEDs. First, we used a delta electrical dipole current source to model an organic emitter and use Maxwell’s equations and the transfer matrix method to deduce the behaviors of electromagnetic waves and power flow in device. Next, we introduced several distribution functions to describe general properties of the emitters in devices. Finally, we combined the results of single emitter and the distribution functions to model planar layered OLEDs.
In the second part of the thesis, we discuss how to measure the horizontal dipole ratio in an OLED emitting layer. Then, we discuss how the horizontal dipole ratio influences the performance of devices.

並列關鍵字

distribution function, horizontal dipole ratio, Maxwell’s equations, organic light-emitting devices

參考文獻

[1] M. Pope, P. Magnante and H. P. Kallmann, Electroluminescence in Organic Crystals, J. Chem. Phys. 38, 2042 (1963)

[2] C. W. Tang and S. A. Vanslyke, Organic electroluminescent diodes, Appl. Phys. Lett. 51, 913 (1987)

[3] J. Kido, M. Kimura and K. Nagai, Multilayer White Light-Emitting Organic Electroluminescent Device, Science 267, 1332 (1995)

[4] Y. Sun and S. R. Forrest, High-efficiency white organic light emitting devices with three separate phosphorescent emission layers, Appl. Phys. Lett. 91, 263503 (2007)

[5] S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency, J. Appl. Phys. 104, 123109 (2008)