有機發光元件之載子傳輸材料及發光材料之特性研究與元件應用

The Characteristics and Device Applications for OLED Carrier-Transporting Materials and Emitting Materials

陳重嘉(Chung-Chia Chen)

指導教授 ： 吳忠幟

國立臺灣大學/電機資訊學院/電機工程學研究所/博士(2010年)

https://doi.org/10.6342/NTU.2010.01450

摘要

在本論文中，我們針對有機發光元件基礎特性到元件的製作進行研究。首先，我們利用頻譜阻抗技術研究摻雜了p型傳輸雜質的電洞傳輸層特性，並建構其等效電路。摻雜有傳輸雜質的電洞傳輸層，由於雜質分佈的影響，必須考量電極附近因能階差異額外形成的空乏區，以及會隨頻率變化的介電質響應，建構等效電路時也必須納入更為複雜的阻抗元件以達到更好的模擬結果。
接著我們試著對有機發光元件的結構做出簡化，利用兼具電洞和電子傳輸能力，並有著高三重階激發態能量的主發光體材料製作單層磷光有機發光元件，我們僅使用單一材料扮演電洞傳輸層、發光層以及電子傳輸層功能，大幅簡化了製作過程，並成功得到了高效率的單層藍光及白光磷光有機發光元件。
我們也以同一種主發光體材料，在僅使用額外各一層電洞及電子傳輸層的相對簡單結構下，實現了三層結構的高效率藍光及白光磷光有機發光元件，相對於現行常見的多層複雜結構，此一簡化的三層結構不僅有著高效率，而且由於主發光體兼具電洞和電子的傳輸特性，磷光元件在高亮度下常見的效率淬熄現象也大為減輕。
最後，我們利用新穎的藍光及紅光銥化合物，在適當的元件結構設計下，得到了適合白光照明應用，在不同照明亮度下皆具有良好演色能力的白光磷光發光元件。

關鍵字

有機發光元件 ； 白光有機發光元件 ； 磷光有機發光元件 ； 阻抗頻譜技術 ； 等效電路 ； 單層有機發光元件 ； 元件結構簡化 ； 演色性指數

並列摘要

In this dissertation, we studied fundamental properties and device architectures for organic light-emitting devices (OLEDs). First, the impedance spectroscopy was adopted to investigate the p-type conductively doped hole transporting layer and to construct equivalent circuits. Because of the addition of conductive dopant, it was found necessary to take account the difference between the bulk region and the depletion region near the electrode, and dispersion (i.e. frequency dependence) in the dielectric response of the conductively doped transport layer. As such, it is found necessary to include the non-conventional complex impedance element in the equivalent circuit to achieve tight matching of simulated results
The second part of the dissertation is about the simplification of OLED device structure. By the aid of the novel host material possessing bipolar transporting capability and high triplet energy, we successfully fabricated efficient single-layer phosphorescent OLEDs Efficient blue and white single-layer phosphorescent OLEDs were demonstrated.
Furthermore, we again adopted the same host material to fabricate conventional multi-layer OLEDs. With only adding a hole-transporting layer and an electron-transporting layer to form a relatively simple three-layer simple structure, very efficient blue and white phosphorescent OLEDs were implemented with small efficiency roll-off.
Finally, we utilized novel Ir-based blue and red phosphors to fabricated efficient white phosphorescent OLEDs (WOLEDs) for solid state lighting (SSL). With carefully designed device architectures, we achieved efficient phosphorescent WOLEDs with high color rendering index over a wide luminance range.

並列關鍵字

OLEDs ； White OLEDs ； Phosphorescent OLEDs ； Impedance Spectroscopy ； Equivalent Circuits ； Single-layer OLEDs ； Simplification of Device Structure ； Color Rendering Index

參考文獻

[2] W. Helfrich and W. G. Schneider, Phys. Rev. Lett. 14, 229 (1965).

[3] C. W. Tang and S. A. VanSlyke, Appl. Phys. Lett. 51, 913 (1987).

[5] C.-C. Wu, C.-W. Chen, C.-L. Lin, and C.-J. Yang, J. Disp. Technol. 1, 248 (2005).

[6] B. W. D’ Andrade and S. R. Forrest, Adv. Mater. 16, 1585 (2004).

[16] S. C. Tse, K. K. Tsung, and S. K. So, Appl. Phys. Lett. 90, 213502 (2007).