位置規則性-聚(3-烷基噻吩)及共聚物之合成與特性探討及其應用於有機場效電晶體之研究

STUDY ON THE SYNTHESIS AND CHARACTERIZATION OF REGIOREGULAR POLY(3-ALKYLTHIOPHENES) AND COPOLYMERS AND APPLICATION ON ORGANIC FIELD-EFFECT TRANSISTOR

孫佩君(Pei-Chun Shun)

指導教授 ： 郭欽湊

大同大學/工程學院/化學工程學系所/碩士(2006年)

摘要

本研究利用Grignard metathesis method 合成出不同側鏈基位置規則性聚(3-烷基噻吩) (P3MT, P3HT, P3OT, P3DT, and 3DDT)。此外也成功合成出不同側鏈基位置規則性聚(3-烷基噻吩)共聚物(P3MHT, P3MOT, P3HDT, and P3DDT)。位置規則性聚(3-烷基噻吩)以及共聚物為一以頭尾(head-to tail)方式進行偶合(coupling)排列之共軛高分子，可輕易的達到一個低能量、低空間障礙的共平面構造，具有高度的共軛性、較佳的導電度及光學性質，並能產生自組裝(self-assembly)之絕緣結構，有利於光電元件的應用，如有機場效電晶體。
本研究中以NMR, FTIR, EA, GPC, XRD, DSC, TGA, TMA, UV, PL及CV 對聚(3-烷基噻吩)及共聚物的性質進行一系列物性探討。由NMR之結果對聚(3-烷基噻吩)及共聚物計算位置規則度為 80% ~ 97% 。聚(3-烷基噻吩)及共聚物的分子量分別是3,900-17,200 g/mol及8,140-34,001 g/mol並具窄小的PDI值。在熱分析方面由DSC得知側鏈越長，熔點越明顯的下降，且由TGA得知於400℃氮氣環境下擁有一良好的的穩定熱性質。以XRD對聚(3-烷基噻吩)及共聚物結果指出，兩者皆具有絕佳的排列及結晶性結構。由UV-visible光譜顯示，聚(3-烷基噻吩)及共聚物會隨著位於規則度的提高而產生紅位移，且聚(3-烷基噻吩)共聚物產生較高的共軛性。也由UV-visible可計算出能隙(Energy gap)，得知聚(3-烷基噻吩)及共聚物有較小的能隙。此外，由PL得知聚(3-烷基噻吩)及共聚物在CHCl3溶液中發橘黃光。由循環伏安儀可計算出氧化電位以及HOMO及LUMO值。
聚(3-烷基噻吩)及共聚物的薄膜電晶體(TFT)特性已被研究。P3HT and P3OT薄膜電晶體 (TFT) 之載子位移率、開關電流比、起始電壓及臨界斜率分別為 2.08 x 10 – 2 cm 2/Vs, 1 x 10 4, 10.5 V, 2.89 V/decade (P3HT) 及3.18 x 10 – 3 cm 2/Vs, 4.4 x 10 3, 10.5 V, 1.43 V/decade (P3OT)。另一方面，以P3MT分別與P3HT 及P3OT形共聚物，薄膜電晶體 (TFT) 之載子位移率、開關電流比、起始電壓及臨界斜率分別為別為1.32 x 10 – 3 cm 2/Vs, 6.4 x 10 4, 12.1 V, 1.79 V/decade (P3MTHT) 及1.79 x 10 – 2 cm 2/Vs, 1 x 10 4, 11.6 V, 2.88 V/decade (P3MTOT).

關鍵字

聚(3-烷基噻吩) ； 位置規則性

並列摘要

The regioregular of poly(3-alkylthiophene) (HT-P3ATs) (P3MT, P3HT, P3OT, P3DT, and P3DDT) with different length of the alkyl side chains can be synthesized successfully by GRIM (Grignard metathesis) method. Besides, we were also successfully synthesized copoly(3-alkyl-
thiophenes) (P3MTHT, P3MTOT, P3HTDT, and P3HTDDT). These polymers containing high percentage of head-to-tail coupling, can be easy of access a low energy, low space obstacle coplanar conformation, leading to highly conjugated polymer. HT-P3ATs and their copolymers possess better conductivity and optical properties, and can undergo self-assembly. And these materials have a significant practical impact in optoelectronic application-organic field-effect transistor (OFET).
The physical properties of these polymers were done by NMR, FTIR, EA, GPC, XRD, DSC, TGA, TMA, UV, PL, and CV. The regioregularity of these samples were calculated to be 80% ~ 97% using by NMR data. It is found that the molecular weights of P3ATs and copolymers were about 3,900-17,200 g/mol and 8,140-34,001 g/mol, respectively. These polymers exhibit a narrow PDI. The thermotropic transition behavior of these materials were examined by DSC, an increased in the length of the side chain decreased remarkably the melting point and exhibit an excellent thermal stability under 400 ℃. The XRD results indicate that poly(3-alkylthiophenes) and copolymers have a great order and crystalline structure. The UV-visible spectra of poly(3-alkylthiophenes) and copolymers show that red shift of λmax increase with increasing the level of regioregularity and that the copolymers has a higher conjugation. The bandgap calculated of poly(3-alkylthiophenes) and copolymers from UV-visible and exhibit a small bandgap. Besides, the poly(3-alkylthiophenes) and copolymers of PL emit yellow-orange light in CHCl3 solution state. The cyclic voltammetry can be calculated the values of oxidation potential, HOMO, and LUMO.
The characteristics of thin-film transistor (TFT) fabricated with P3ATs and copolymers have been investigated. The charge transport mobility, on/off current ratio, threshold voltage and subthreshold slope of P3AT OTFTs are 2.08 x 10 – 2 cm 2/Vs, 1 x 10 4, 10.5 V, 2.89 V/decade (P3HT) and 3.18 x 10 – 3 cm 2/Vs, 4.4 x 10 3, 10.5 V, 1.43 V/decade (P3OT), respectively. The charge transport mobility, on/off current ratio, threshold voltage and subthreshold slope of copolymer OTFT are 1.79 x 10 – 2
cm 2/Vs, 1 x 10 4, 11.6 V, 2.88 V/decade (P3MTOT) and 1.32 x 10 – 3 cm 2/Vs, 6.4 x 10 4, 12.1 V, 1.79 V/decade (P3MTHT), respectively.

並列關鍵字

poly(3-alkylthiophene) ； semiconductor

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