位置規則性聚噻吩及其共聚物之合成及其應用於有機場效電晶體特性之研究

STUDIES ON THE SYNTHESIS AND APPLICATION OF REGIOREGULAR POLYTHIOPHENES AND COPOLYMERS ON THE CHARACTERISTICS OF ORGANIC FIELD-EFFECT TRANSISTOR

徐川順(Chuan-Shun Syu)

指導教授 ： 郭欽湊

大同大學/工程學院/化學工程學系所/碩士(2007年)

摘要

本研究利用Grignard metathesis 合成不同側鍵烷基高位置規則性三種聚(3-烷基噻吩)(P3HT, P3OT, P3DDT)及六種共聚物(PT-co-P3HTⅠ , P3HT-co-P3OTⅠ, P3HT-co-P3DDTⅠ, P3HT-co-P3DDTⅡ, P3MOT-co-P3DDT, and P3MOT-co-P3HT)。位置規則性聚(3-烷基噻吩)及其共聚物為-以頭對尾方式進行偶合排列之共軛高分子，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。
研究中，以NMR， FTIR， GPC,，XRD，UV，PL， DSC，和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對聚(3-烷基噻吩)及共聚物鑑定並計算位置規則度。聚(3-烷基噻吩) 及共聚物的分子量分別是7702~8754 g/mol及7784~26671 g/mol並有不錯的PDI值。以XRD對聚(3-烷基噻吩) 及共聚物結果指出，兩者皆具有好的排列及結晶性結構。由UV-visible 光譜顯示，以P3AT位置規則度提高在光譜中會有紅位移(red shift)產生；而增長烷基側鏈基之長度則會造成藍位移(blue shift)，說明了高位置規則度P3AT具有高共軛度，而過長之側鏈烷基則會降低其共軛性。而共聚物是隨著側鍵基的長度越長會有紅位移(red shift)產生，即側鍵烷基越長則會提高共軛性。
由UV-visible可計算出能隙，聚(3-烷基噻吩) 及共聚物具較小的能隙約1.8 eV。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 HOMO值為5.01~5.42 eV及LUMO為3.19~3.57 eV值。此外，聚(3-烷基噻吩) 及共聚物熔點會隨著側鏈烷基長度減少而提升。
將聚(3-己基噻吩)及共聚物應用作為有機薄膜電晶體之半導體材質，其特性為P3HT 載子位移率、開關電流比分別 2.08 × 10–2 cm2/Vs, 9.74 × 103共聚物載子位移率、開關電流比分別1.64 × 10–3 cm2/Vs，8.36 × 103 (PT-co-P3HTⅠ)， 8.96 × 10-3 cm2/Vs，5.11 × 105 (P3HT-co-P3OTⅠ)， 2.87 × 10–3 cm2/Vs，7.52 × 103 (P3HT-co-P3DDTⅠ)，and 9.57 × 10–3 cm2/Vs，7.35 × 105 (P3HT-co-P3DDTⅡ)，發現共聚物之分子量愈大，特性愈好。

關鍵字

位置規則性聚噻吩及其共聚物

並列摘要

Three regioregular poly(3-alkylthiophenes) (P3ATs: P3HT, P3OT, and P3DDT) and six kinds of copolymers (PT-co-P3HTⅠ, P3HT-co-P3OTⅠ, P3HT-co-P3DDTⅠ, P3HT-co-P3DDTⅡ, P3MOT-co-P3DDT, and P3MOT-co-P3HT) have been synthesized successfully by Grignard metathesis. These poly(3-alkylthiophenes) and it’s copolymers, 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 character, better conductivity and optical property.
The physical properties of these polymers were done by NMR, FT-IR, GPC, XRD, UV, PL, DSC, and CV. The structure and regioregularity of P3ATs and copolymers were identified by NMR analysis. It is found that the regioregularity of all samples is larger than 90 %. The molecular weight of P3ATs and copolymers were 7702~8754 g/mol, and 7784~26671 g/mol, respectively. They exhibit a narrow molecular weight distribution (PDI = 1.22~2.14). The XRD results indicate that P3ATs and copolymers have a great order and crystalline structure. The UV-visible spectra of poly(3-alkylthiophenes) show that the λmax increases with increasing the level of regioregularity, resulting in the phenomena of red shift. λmax of P3ATs increases with increasing the length of the alkyl side chain resulting in the phenomena of blue shift. The conjugation length increases with increasing regioregularity and decreasing with increasing the lengths of alkyl side chain. However, the conjugation length increases with increasing the length of the alkyl side chain of copolymer. The bandgap of poly(3-alkylthiophene) and copolymers is about 1.8 eV. Besides, the poly(3-alkylthiophene) and copolymers emit yellow-orange light in CHCl3 solution measured by PL. The oxidation potential and the values of HOMO (5.01~5.42 eV) and LUMO (3.19~3.57 eV) can be calculated by the cyclic voltammetry. It is found that the Tm of P3ATs and copolymers decreases with increasing the length of the alkyl side chain.
The characteristics of organic thin-film transistor fabricated with P3ATs and copolymers acted as semiconducting materials have been carried out. The charge transport mobility and on/off current ratio of P3HT OTFT are 2.08 × 10–2 cm2/Vs and 9.74 × 103. The charge transport mobility and on/off current ratio of copolymers OTFT are 1.64 ×10–3 cm2/Vs, 8.36 × 103 (PT-co-P3HTⅠ), 8.96 × 10-3 cm2/Vs, 5.11 × 105 (P3HT-co-P3OTⅠ), 2.87 × 10–3 cm2/Vs, 7.52 × 103 (P3HT-co-P3DDT Ⅰ), and 9.57 × 10–3 cm2/Vs, 7.35 × 105 (P3HT-co-P3DDTⅡ) respectively. It is found that the characteristics of transistor increases with increasing the molecular weight of copolymers.

並列關鍵字

STUDIES ON THE SYNTHESIS AND APPLICATION OF REGI

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