間三聯苯噁二唑電子傳輸材料之設計合成與應用於磷光有機發光二極體

Design and Synthesis of meta-Terphenyloxadiazole Derivatives as Electron Transporting Materials for Phosphorescent Organic Light-Emitting Diodes

施承宏(Cheng-Hung Shih)

指導教授 ： 鄭建鴻

國立清華大學/理學院/化學系/碩士(2013年)

摘要

由於文獻中報導間三聯苯結構具有高三重態能隙及好的熱穩定性，同時噁二唑基團具有很好的成膜性及傳導電子的性質，因此在本論文中結合了間三聯苯基團和噁二唑基團，設計合成出5種電子傳輸材料PhOXD、FOXD、3PyOXD、4PyOXD及TPOTP。此系列材料的LUMO能階主要由噁二唑基團所貢獻，因此藉由修飾噁二唑基團上的取代基可以達到調整LUMO能階的作用；另外，這系列材料的三重態能隙介於2.62~2.88 eV之間並具有良好的熱性質表現，可應用於RGB三色磷光元件。在單一電子元件方面，我們比較市售的OXD-7、TAZ、BAlq、BCP/Alq3及實驗室學長所發表的tOXD-mTP，結果顯示這系列材料均有不錯的電子移動率。以CzPPQ為主體材料的紅色磷光系統中，搭配3PyOXD為電子傳輸層，其最大外部量子效率可達26.6%，電流效率可達33.5 cd/A，CIE座標(0.67, 0.33)；以BCPO為主體材料的綠色磷光系統中，搭配PhOXD為電子傳輸層，其最大外部量子效率可達26.3%，電流效率可達101.7 cd/A，CIE座標(0.29, 0.64)；以BCPO為主體材料的藍色磷光系統中，搭配PhOXD為電子傳輸層，最大外部量子效率達26.4%，最大電流效率可達55.0 cd/A，CIE座標(0.14, 0.32)。

關鍵字

間三聯苯 ； 電子傳輸 ； 有機發光二極體 ； 磷光 ； 噁二唑

並列摘要

In the literature, m-terphenyl-modified materials have shown high triplet energy gap and thermal stability while utilizing oxadiazole-based materials as electron-transporting materials. Therefore, in this thesis, we developed five electron transport materials: PhOXD, FOXD, 3PyOXD, 4PyOXD and TPOTP by introduction of m-terphenyl and oxadiazole moieties. The LUMO levels of these materials relied on the linkage of oxadiazole moieties; as a result, we could adjust the LUMO levels of these materials by modifying the functional groups on oxadiazole moieties. In addition, the triplet energy gaps were determined to be 2.62-2.88 eV and they also showed good thermal stability which could be suitable for various phosphors in PhOLEDs. In order to assess the electron transport properties, the electron-only devices were fabricated with these materials and commercial available materials: OXD-7, TAZ, Balq and BCP/Alq3. As expexted, our ETMs exhibit the better electron mobility than commericals. In red PhOLED, the best device using CzPPQ as a host and 3PyOXD as an ETM shows a maximum EQE of 26.6% and a maximum CE of 33.5 cd/A with CIE coordinates of (0.67, 0.33). In green PhOLED, the best device using BCPO as a host and PhOXD as an ETM exhibits a maximum EQE of 26.3%, a maximum CE of 101.7 cd/A with CIE coordinates of (0.29, 0.64). In blue PhOLED, the best device using BCPO as a host and PhOXD as an ETM exhibits a maximum EQE of 26.4%, a maximum CE of 55.0 cd/A with CIE coordinates of (0.14, 0.32).

並列關鍵字

meta-terphenyl ； electron transporting ； Organic light-emitting diodes ； phosphorescent ； oxadiazole

參考文獻

4.C. W. Tang, S. A. VanSlyke, Appl. Phys. Lett., 1987, 51, 913.

10.T. Förster, Disc. Faraday Soc., 1959, 27, 7.

11.D. L. Dexter, J. Chem. Phys., 1953, 21, 836.

18.S. Tokito, H. Tanaka, K. Noda, A. Okada, Y. Taga, IEEE Trans. Elec. Dev., 1997, 44, 1239.

2.H. Antoniadis, M. A. Abkowitz, B. R. Hsieh, Appl. Phys. Lett., 1994, 65, 2030.