新型有機發光材料的光物理與元件特性研究

在本論文中，我們研究新型有機發光材料的光物理與元件特性。首先，我們發現磷雜-2,4-環戊二烯寡聚物的光物理及電激發光特性可以藉著改變其2,5位及磷位取代基來調整。磷雜-2,4-環戊二烯的金錯合物具有寬廣的雙峰發光頻譜，可能有白光有機發光元件的應用性。接著我們研究二個具有旋環雙芴基的高效率發光離子性銥錯合物之光物理特性和其發光電化學元件特性。它們的純膜量子產率仍保有在低濃度下的50 %以上，這證明了旋環雙芴基提供良好的空間阻隔性，抑制了純膜裡的自我猝熄效應。採用這二個材料的發光電化學元件其外部量子效率皆可達7 %以上。為了進一步減低發光材料在薄膜裡的自我猝熄效應，以提高元件效率，我們將這二個具有旋環雙芴基的離子性銥錯合物中具較低能階者(客體)摻雜在具較高能階者(主體)中，成為主-客體系統，並研究其光物理特性。在適當摻雜濃度下，主-客體系統薄膜量子產率比純主、客體的薄膜量子產率高了約50 %，證實主-客體系統拉大了發光基團的距離，大幅抑制了自我猝熄效應。以具有旋環雙芴基的離子性銥錯合物製作的主-客體發光電化學元件，其外部量子效率可以提升至超過10 %。最後，我們分別以藍綠及紅光離子性銥錯合物為主、客體材料來製作白光發光電化學元件，其功率效率可達7.8流明/瓦，電激發光頻譜的演色度高達80，具有白光固態照明的應用潛力。

關鍵字

有機發光二極體；磷雜-2,4-環戊二烯；發光電化學元件；銥；空間阻隔；白光

並列摘要

In this thesis, we study the photophysical and electroluminescent (EL) properties of various novel organic light-emitting materials. First, we show that the photophysical and EL properties of phosphole-based oligomers can be tailored by variation of the 2,5-substitution pattern of phospholes and chemical modification of their P atoms. Phosphole-based gold complexes have broad dual-emitting emission spectra, which may be useful in applications of white organic light-emitting diodes. Next, we study the photophysical properties and the light-emitting electrochemical cells (LECs) of two diazaspirobifluorene-based cationic iridium complexes. Their superior steric hindrance is confirmed by their highly retained photoluminescence quantum yields (PLQYs) in neat films (> 50 % of the PLQYs for both complexes dispersed in a high-gap solid-state host matrix). The LECs based on neat films of these complexes possess high external quantum efficiencies (EQEs) over 7 %. To further reduce self-quenching of excited-states in neat-film emissive layers, which deteriorates the device efficiency, the complex with a lower bandgap (guest) is doped in that with a higher bandgap (host) to form a host-guest system. The host-guest films are shown to exhibit 1.5X higher PLQYs than neat films of host or guest, indicating suppressed self-quenching. The EQEs of the LECs based on optimized host-guest diazaspirobifluorene-based cationic iridium complexes are enhanced to exceed 10 %. Finally, white LECs based on host-guest cationic iridium complexes (blue-green emitting complex as the host and red-emitting one as the guest) are demonstrated. These white LECs exhibit power efficiency of 7.8 lm/W and EL spectra with high color rendering indices up to 80, suggesting their potential applications in solid-state lighting.

並列關鍵字

organic light-emitting diodes ； phospholes ； light-emitting electrochemical cells ； iridium ； steric hindrance ； white light

參考文獻

[2] K. T. Wong, Y. Y. Chien, R. T. Chen, C. F. Wang, Y. T. Lin, H. H. Chiang, P. Y. Hsieh, C. C. Wu, C. H. Chou, Y. O. Su, G. H. Lee and S. M. Peng, J. Am. Chem. Soc. 124, 11576 (2002).

[4] C. C. Wu, Y. T. Lin, K. T. Wong, R. T. Chen and Y. Y. Chien, Adv. Mater. 16, 61 (2004).

[5] T. C. Chao, Y. T. Lin, C. Y. Yang, T. S. Hung, H. C. Chou, C. C. Wu and K. T. Wong, Adv. Mater. 17, 992 (2005).

Chapter 1

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

國際替代計量

新型有機發光材料的光物理與元件特性研究

全文下載

主題瀏覽