含新穎銥錯合物染料之 超高效率綠光有機發光二極體

Highly Efficient Green Organic Light Emitting Diode with a Novel Solution Processable Iridium Complex Emitter

李倢如(Chieh-Ju Li)

指導教授 ： 周卓煇

國立清華大學/工學院/材料科學工程學系/碩士(2013年)

摘要

綠光是製備多波段白光的主要光色，也是典型RGB全彩技術的關鍵組成光色，再由於人眼對綠光的亮度感受度最高，使得綠光成為組成高效率白光的最關鍵成份，因此，創新研發高效率綠光元件便為重要；而對有機發光二極體(Organic Light Emitting Diode, OLED)元件而言，濕式製作具有低的製作成本、能大面積滾印(roll-to-roll)的可能性種種好處；因此，本論文特別探討如何利用一個可濕式製作的綠光發光層，以製作高效率綠光元件。本論文利用一新穎銥錯合物綠磷光染料bis[5-methyl-8-trifluoromethyl-5H-benzo(c)(1,5)aphthyridin-6-one]iridium (pyrazinecarboxylate)，經由適當的主體材料搭配後所製備之元件，在亮度為1,000 cd m-2時，能量效率為60.8 lm W-1，外部量子效率及電流效率則分別為23.8 %和95.6 cd A-1，該能量效率為濕式製作OLED的世界紀錄。此元件之高效率可歸因於：一、利用無電子注入能障之主體材料，促使身為少數載子的電子，可以更有效注入，並與電洞達到更佳的注入平衡，二、良好的主客體能階搭配，在低電壓下時，讓激子於客體上產生及放光，而在高電壓下，載子可以有效在主體上結合，形成激子並傳遞能量給客體放光。

關鍵字

有機發光二極體

並列摘要

Green light is both the major component for the fabrication of multi-band composing white light and the key color of the typical RGB full-color technology. Moreover, it is also the most critical composition for the highly efficient white light since luminous sensitivity of human eyes is the highest with green light. Therefore, innovatively developing a high-efficiency green device is quite crucial. For the organic light emitting diodes (OLEDs), on the other hand, solution process is a promising technology to realize roll-to-roll production and to achieve low-cost probability. We hence study in this thesis the fabrication of a highly efficient green OLED device with a solution-processable emissive layer. We demonstrate a high-efficiency green OLED with a solution-processed emissive layer composing a novel green light emitting iridium complex, bis[5-methyl-8-trifluoromethyl-5H-benzo(c)(1,5) aphthyridin-6-one]iridium (pyrazinecarboxylate). By coupling with a proper host, the green device shows at 1,000 cd m-2 an external quantum efficiency of 23.8%, current efficiency of 95.6 cd A-1, and efficacy of 60.8 lm W-1, the highest among all reported solution-processed OLEDs. The high efficiency may be attributed to the host possessing a zero electron injection barrier, resulting in a more balanced carrier-injection. Besides, the paired host and guest energy-levels allow excitons to generate on the guest predominantly at low voltage, but with increasing excitons generating on the host with the increasing voltage.

並列關鍵字

Organic Light Emitting Diode

參考文獻

74. 陳昱霖, 以天藍光染料製作高效率紫藍光有機發光二極體, 國立清華大學材料科學與工程研究所, 2012, 17.

14. J. H. Jou, M. F. Hsu, W. B. Wang, C. L. Chin, Y. C. Chung, C. T. Chen, J. J. Shyue, S. M. Shen, M. H. Wu, W. C. Chang, C. P. Liu, S. Z. Chen and H. Y. Chen, "Solution-Processable, High-Molecule-Based Trifluoromethyl-Iridium Complex for Extraordinarily High Efficiency Blue-Green Organic Light-Emitting Diode", Chemistry of Materials, 2009, 21, 2565-2567.

28. J. H. Jou, C. C. Chen, Y. C. Chung, M. T. Hsu, C. H. Wu, S. M. Shen, M. H. Wu, W. B. Wang, Y. C. Tsai, C. P. Wang and J. J. Shyue, "Nanodot-enhanced high-efficiency pure-white organic light-emitting diodes with mixed-host structures", Advanced Functional Materials, 2008, 18, 121-126.

13. D. Tanaka, H. Sasabe, Y. J. Li, S. J. Su, T. Takeda and J. Kido, "Ultra high efficiency green organic light-emitting devices", Japanese Journal of Applied Physics Part 2-Letters & Express Letters, 2007, 46, L10-L12.

96. D. Tanaka, H. Sasabe, Y. J. Li, S. J. Su, T. Takeda and J. Kido, "Ultra high efficiency green organic light-emitting devices", Japanese Journal of Applied Physics Part 2-Letters & Express Letters, 2007, 46, L10-L12.