磷光有機發光二極體(Phosphorescent Organic Light-Emitting Diode, PHOLED)利用磷光發光性物質摻雜於高分子主發光體中，因為其便宜的濕式製程和理論上可以達到100%的內部量子效率，吸引了很多人的關注。在磷光有機發光二極體元件中，主發光體需具有足夠大的三重激發態能階(ET)才能避免能量回傳的發生，然而使用的主發光體材料的能階差(Eg)通常較大，電荷由電極注入時所需克服的能障相對增大，本研究把雙極性分子導入主發光體中，利用雙極性分子的優異電子、電洞傳遞性質，使電子、電洞在發光層中平衡以達到高的元件效率。
本研究在高分子結構設計上，導入具電洞傳輸能力的carbazole和具電子傳輸能力的triazole所組成的雙極性基團，以幫助電子和電洞傳輸平衡。然而因雙極性單體的溶解度不佳，因此導入烷氧鏈(三甘醇醚)增加溶解度，利用Suzuki coupling反應合成共聚合物P1、P2，其中P1具有不錯的熱穩定性，HOMO及LUMO能階分別為-5.47 eV及-2.48 eV，顯示導入的雙極性基團確實可以提高HOMO能階，降低LUMO 能階，幫助電荷注入發光層，且具有很高的三重激發態能階(3.0 eV)，可以當作藍光主發光體的材料。

Phosphorescent polymer light-emitting diodes (PhPLEDs) based on phospho-rescent dopants dispersed in a polymeric host have attracted extensive attention because of their inexpensive solution-processing techniques and theoretical 100% internal quantum efficiencies. The host materials of PHOLEDs are usually with high triplet energy level (ET) to prevent energy back transfer from the guest materials. In order to improve charge transport and achieve balanced charges injection, bipolar groups were introduced into molecular structure. Bipolar groups enhance injection and transport for both carriers, facilitating balanced charge fluxes in the emitting layer, resulting in high device efficiencies.
In this study, we designed and successfully synthesized a bipolar dibro-mo-monomer (M1) containing hole-transporting moiety (carbazole derivative) and electron-transporting group (triazole derivative). Two copolymers (P1, P2) were synthesized by the Suzuki coupling reaction of the dibromo-monomer (M1) and triethylene glycol di-4-bromobenzyl ether (10) with 1,4-benzenediboronic acid bis(pinacol) ester (11). The soft triethylene glycol ether was incorporated into main chain to increase the solubility of the copolymers. Thermal decomposition temperature (at 5% weight loss) of P1 and P2 was around 365oC. The HOMO and LUMO levels of P1 were -5.47 eV and -2.48 eV, respectively, as estimated from its cyclic voltammogram. It is clear that the bipolar groups indeed raise HOMO energy level and lower LUMO energy level simultaneously, facilitating the injec-tion/transport of both carriers. More importantly, the estimated triplet energy level (ET) is very high (3.0 eV), which can be used as polymeric hosts for blue-emitting PhPLEDs.

[1]郭昭輝；塑膠資訊雜誌，民國91 年10 月
[2] Skoog, D. A.; West, D. M.; Holler, F. J. Fundamentals of Analytical Chemistry, 5th edition, Saunders College Publishing, 1988.
[3] Turro, N. J. Modern Molecular Photochemistry, Mill Valley,
University Science Books, California, 1991.
[4] Skoog, D. A.; Holler, E. J.; Nieman, T. A. Principles of Instrumental, Analysis, 5th edition, Saunders College Publishing, 1997.
[5] 翁文國；工業材料雜誌，第156 期，P.75，民國88 年12 月.
[6] Hadziioannou, G.; van Hutten, P. F. Semiconducting Polymers:
Chemistry, Physics and Engineering, Wiley-VCH, 1999.
[7] Miyaura, N. et al. Tetrahedron Lett. 1979, 3437.
[8] Miyaura, N.; Suzuki, A. Chem. Commun. 1979, 866.
[9] Chen, F.-C.; He, G.; Yang, Y. Applied Physics Letters 2003, 82, (7),1006-1008.1006-1008.
[10] Pai, D. M.; Yanus, J. F.; Stolka, M. The Journal of Physical Chemis-try1984, 88, (20), 4714-4717.
[11] Gong, X.; Robinson, M. R.; Ostrowski, J. C.; Moses, D.; Bazan, G. C.;Heeger, A. J. Advanced Materials 2002, 14, (8), 581-585.
[12] Kanai, H.; Ichinosawa, S.; Sato, Y. Synthetic Metals 1997, 91, (1-3), 195-196.
61
[13] Ikai, M.; Tokito, S.; Sakamoto, Y.; Suzuki, T.; Taga, Y. Applied Phys-ics Letters 2001, 79, (2), 156-158.
[14] Holmes, R. J.; D'Andrade, B. W.; Forrest, S. R.; Ren, X.; Li, J.;
Thompson, M. E. Applied Physics Letters 2003, 83, (18), 3818-3820.
[15] Ren, X.; Li, J.; Holmes, R. J.; Djurovich, P. I.; Forrest, S. R.; Thompson, M. E. Chemistry of Materials 2004, 16, (23), 4743-4747.
[16] Gong, S.; Chen, Y.; Yang, C.; Zhong, C.; Qin, J.; Ma, D. Advanced Materials 2010, 22, (47), 5370-5373.
[17] Yeh, S. J.; Wu, M. F.; Chen, C. T.; Song, Y. H.; Chi, Y.; Ho, M. H.; Hsu, S. F.; Chen, C. H. Advanced Materials 2005, 17, (3), 285-289.
[18] PROGRESS IN CHEMISTRY Vol . 18 No. 5 May , 2006
[19] 趙慶勳，郭耀興，段啟聖：化工資訊雜誌，P.18，2002 年5 月.
[20] Chen, Z. K.; Meng, H. ; Lai, Y.; Huang, H.W. Macromolecules, 32, 4351 (1999).
[21] Bao, Z.; Peng, Z.; Galvin, M. E.; Chandross, E. A. Chem. Mater., 10, 92 1201 (1998).
[22] Grice, A. W.; Tajbakhsh, A.; Burn, P. L.; Bradley, D. D. C. Adv. Ma-ter.,9, 1174 (1997).
[23] Kraft, A.; Grimsdale, A. C. and Holmes, A. B. Angew : Chem. Int.Ed., 37, 402 (1998).
[24] Joseph, R.; Lakowicz, R. Principles of Fluorescence Spectroscopy,
62
Kluwer Academic/Plenum Publishers, New York, 1999, p368.
[25] Lamola, A.; Turro, N. J. Energy Transfer and Organic Photochemistry, Wiley & Sons, New York, 1969.
[26] Shirota, Y.; Kageyama, H. Chemical Reviews 2007, 107, (4), 953-1010.
[27] Jenekhe, S. A.; Yi, S. Applied Physics Letters 2000, 77, (17), 2635-2637.
[28] Saragi, T. P. I.; Spehr, T.; Siebert, A.; Fuhrmann-Lieker, T.; Salbeck, J. Chemical Reviews 2007, 107, (4), 1011-1065.