利用Suzuki耦合反應於三苯胺為主體之共軛高分子合成、性質探討及其在螢光開關元件上的應用

Utilizing Suzuki Coupling Reactions in the Synthesis of Triphenylamine-Based Conjugated Polymers, Their Physical Properties and Application in Electrofluorochromic Devices

郭政柏(Cheng-Po Kuo)

指導教授 ： 梁文傑

國立臺灣大學/理學院/化學研究所/博士(2013年)

https://doi.org/10.6342/NTU.2013.01287

摘要

在本論文中，我們利用Suzuki耦合反應合成一系列以三苯胺為主體之共軛高分
子。藉由紫外光吸收、光致放光光譜儀等光物理測量，以及循環伏安法電化學量測，對此系列之高分子性質進行探討。在第二章中，由電化學的測量得知以三苯胺為主體之共軛高分子具有良好的氧化還原特性。在光物理性質的探討中，由光致放光光譜得知其共軛高分子為藍色螢光，並且具有高螢光量子效率。我們發現，其高分子薄膜在電化學氧化的狀態下，其原本的藍色螢光會被淬熄。因此，我們進一步將其應用在螢光開關元件之主體材料，由電化學結合光譜儀測量，發現可以藉由電化學氧化還原來調控其螢光開關之可逆行為。最高之螢光對比率(contrast ratio)為16.3。
在第三章中，我們想設計出以共軛高分子為主體材料之白色螢光開關元件。首先，要得到白光元件，可由藍光＋綠光＋紅光等形成互補色白光；或者是利用藍光加上其互補色之黃光來形成白光。因此，我們在三苯胺以及茀為主體之共軛高分子中加入拉電子基團(benzo[2,1,3]thiadiazole)，可調控其螢光為黃色螢光。並且將其製作成黃光開關元件，可得到螢光高對比率為21.4。接著，我們更進一步將其黃光共軛高分子摻混到藍光共軛高分子中，可成功得到高螢光量子效率之白光開關元件。其最高螢光對比率為14.6。
在第四章中，我們將layer-by-layer (LbL) assembly 的技術應用在螢光開關元件上。因此，我們合成出含有鹽類基團的共軛高分子為藍色螢光，此高分子可溶於水以及甲醇，與市售的poly(diallyldimethylammonium chloride) (PDDA) 利用旋轉塗佈法結合LbL assembly 的技術製作多層膜，利用膜厚量測、紫外光吸收、以及循環伏安法電化學量測得知其多層膜的增長。接著，我們更進一步將其製作藍色螢光開關元件。其最高螢光對比率為5.20。

關鍵字

螢光開關元件 ； 共軛高分子 ； 三苯胺 ； 茀 ； 光致放光

並列摘要

We report the study of the electrochemical fluorescence switching properties of the conjugated copolymers containing fluorene, triphenylamine, and 1,3-diphenyl- imidazolidin-2-one moieties in chapter 2. The polymers of P1 and P2 show high fluorescence quantum yields, excellent thermal stability, and good solubility in polar organic solvents. While the polymer of P2 emits blue light under UV irradiation, the fluorescence intensity is quenched upon electrochemical oxidation. The fluorescent behavior can be reversibly switched between non-fluorescent (oxidized) state and strong fluorescence (neutral) state with a high contrast ratio (If/If0) of 16.3. The role of the electrochemical oxidation of the triphenylamine moieties is to generate the corresponding radical cations that lead to fluorescence quenching in the solid matrix.
In light of the importance of the white-light emitting devices, we are interested in preparing conjugated polymers with high emission efficiency. In addition, to achieve a white-light emitting electrofluorochromic device (EFD), the emission spectral range should cover, in principle, three basic colors of red, green, and blue. Another alternative in the emission spectral range covers two compensating blue and yellow colors. In chapter 3, we are interested in further developing novel PF based polymer of PFBT1 that have the color-tuned through incorporation of the electron-deficient benzo[2,1,3]thiadiazole (BT) units so that the emission could cover a wider range to yellow color spectral region. The copolymer of PFBT1 shows excellent thermal stability and good solubility in polar organic solvents that benefit thin-film fabrication. While the electrofluorochromic device (EFD) of PFBT1 emits yellow light under UV excitation, fluorescence intensity is switched off upon electrochemical oxidation. The fluorescent behavior of the EFD of PFBT1 can be reversibly switched between the non-fluorescent (oxidized) state and the fluorescent (neutral) state with a superb contrast ratio (If/If0) of 21.4. Furthermore, a white-light electrofluorochromic device is achieved by blending of PFBT1 (yellow) with P2 (blue). Since the emission of fluorescent conjugated polymers of PFBT1 and P2 could be simultaneously quenched under the low working potential, the EFD shows white-dark state of fluorescence with a high contrast ratio (If/If0) of 14.6.
An alternative, promising approach to fabrication of nanostructured films is the layer-by-layer (LbL) assembly technique, which is based on the sequential adsorption of polycations and polyanions (or hydrogen-bond donors and acceptors) from dilute aqueous solution onto a solid substrate. The LbL method has been shown to form low-roughness electroactive polymer ultrathin films of exceptional homogeneity and high electrical conductivity. In chapter 4, a novel electrofluorochromic conjugated polyelectrolyte, PFTSO3Na as an polyanion, was synthesized and used in the fabrication of layer-by-layer (LbL) assembled multilayer film with poly(diallyldimethylammonium chloride) (PDDA) as a polycation. While the electrofluorochromic device (EFD) is fabricated by multilayer film of PFTSO3Na/PDDA which emits blue light under UV excitation, the fluorescence intensity of the EFD is switched off upon electrochemical oxidation. Moreover, the electrofluorochromic behavior of the EFD can be reversibly switched between the non-fluorescent (oxidized) state and the fluorescent (neutral) state with a contrast ratio (If/If0) of 5.20.

並列關鍵字

electrofluorochromic device ； electrofluorochromism, fluorene, triphenylamine ； 1,3-diphenyl-imidazolidin-2-one ； layer-by-layer assembly

參考文獻

Chapter 6

6.1 Reference list of chapter 1

1. Kim, J.; You, J.; Kim, E. Macromolecules 2010, 43, 2322.

5. Huang, X.; Xiao, Y.; Lang, M. Macromol. Res. 2011, 19, 113.

6. Gomathi, P.; Ghim, H. D.; Ragupathy, D. Macromol. Res. 2011, 19, 442.