發藍光高分子材料的合成與性質研究及其在有機發光二極體的應用

Abstract

本論文分為兩部分，分別針對兩種不同的聚茀高分子發光材料之合成、性質與元件做討論。 在A 部分中, 我們合成出一具有螺結結構之poly(terfluorene), PTF.。在螺結雙茀結構中，相互垂直的雙茀共軛部分藉由一個四級碳原子連接，因此可有效地控制高分子的共軛長度。螺結結構的導入，使PTF具有良好的熱穩定性,且有效抑制分子堆疊與激發複合體的產生。此處利用化合物B5掺混入PTF中來調整元件光色，其元件之EL光譜圖在不同電壓下具有良好的穩定性。 在B部分中，我們利用Suzuki coupling聚合反應，將含triphenylamine之單體(化合物B3) 、 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)- 9,9 -dioctyl-fluorene (化合物B4)與2,7-dibromo-9,9-dioctylfluorene以不同比例合成出一系列的高分支狀聚茀高分子衍生物。此處所合成出的高分支狀聚茀高分子衍生物，對於一般有機溶劑具有良好的溶解度且易成膜。隨著化合物B3導入的比例越高時，玻璃轉移溫度(Tg)由114℃提升至248℃，其Tg皆明顯較POF(Tg = 75℃)高。此處所合成的高分支狀高分子，無論在光激發光或電激發光皆具有良好的光色穩定性。

In part A, we have synthesized a spiro-linked poly(terfluorene), PTF. In the spiro-fused bifluorene segment, the two mutually perpendicular fluorene rings were connected via a common tetracoordinated carbon atom, which served as a conjugation interrupt to effectively control the conjugation length of the polymer. Attributed to the spiro structure, the polymer exhibited a very good thermal stability and suppress the formation of aggregating/excimers. B5 was doped into PTF to tune device color and the device exhibits stable EL spectra which are independent of applied voltages.

In part B, a series of hyperbranched polyfluorene derivatives were prepared by Suzuki coupling copolymerization of a rigid triphenylamine-containing B3 monomer、2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)-9,9-dioctyl- fluorene , or with 2,7-dibromo-9,9-dioctylfluorene. These hyperbranched polymers exhibited good solubility in common organic solvents as well as facile film forming properties. The glass transition temperature (Tg) of the hyperbranched polymer increases as the content of B3 monomer is increased, increased from 114 ℃ to 248 ℃,which are significantly higher than Tg of polyfluorene homopolymer. The emissions of these hyperbranched polymers show good spectral stability upon either optical or electrical excitation.