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Title: | 新穎具噻吩側鏈之硒吩共軛高分子:合成、形態鑑定及其於有機光電元件之應用 New Selenophene-Containing Conjugated Polymers with Thiophene Side Chains:Syntheses, Morphology and Organic Optoelectronic Device Applications |
Authors: | Chi-Chou Chiu 邱啟洲 |
Advisor: | 陳文章 |
Keyword: | ?吩側鏈,硒吩共軛高分子,有機光電元件, Thiophene Side Chains,Selenophene-Containing Conjugated Polymers,Organic Optoelectronic Device Applications, |
Publication Year : | 2014 |
Degree: | 碩士 |
Abstract: | 共軛高分子近年來在光電元件上的應用相當受到囑目,主要是因為其在多種可撓曲電子元件上具有很大的潛能等優異特性。共軛高分子之化學結構和形態是影響電子與光電特性的主要因素。在本論文中,系統性地研究電子施體-施體共軛有機材料的合成、光電特性與元件性質。研究目的著重在下列幾個方向:(1)設計與合成新穎電子施體-施體共軛有機材料,(2)釐清光電性質、薄膜表面形態以及化學結構之間的關係,以及(3)分析電子施體-施體共軛有機材料在光電元件上的性質,如薄膜電晶體或是光伏打電池元件。此研究的主題與細節將整理如下:
1.以硒吩為基礎之噻吩共軛側鏈段之新穎共軛高分子合成與特性鑑定(第二章):利用硒吩為基礎之噻吩共軛側鏈段(4TSe)單體分別和不同之單元(V、T、2T與TT)合成出電子施體-施體共軛高分子 ( PSe4TV、PSe4TT、PSe4T2T、 PSe4TTT 和 P2Se4TTT ),得知其高分子結構對於分子能階,熱性質以及表面形態具有高度相關性的。這些高分子之能隙順序為 P2Se4TTT< PSe4TTT < PSe4TV < PSe4T2T < PSe4TT。我們發現 P2Se4TTT 具有最小的能隙,主要是因為內嵌的雙硒吩可以有效降低共軛側鏈段的立體障礙。另外,P2Se4TTT 也具有最低的玻璃轉移溫度以及呈現纖維狀的表面形態,也是因為內嵌的雙硒吩可建構出反對稱的結構,進而利於分子間的運動以及排列。 2.以硒吩為基礎之噻吩共軛側鏈段之新穎共軛高分子應用於高效能之薄膜電晶體及太陽能電池元件(第三章):此章節主要探討高分子結構對於電荷遷移率及光伏打電池特性的關聯性。其中,P2Se4TTT 由於具有高度的結晶性排列而表現最高的電洞遷移率可以高達0.263 cm2 V-1 s-1¬,同時也有高的電流開關比為1.30×105。另外,對於共軛高分子混摻碳六十衍生物做為太陽能電池主動層的系統,P2Se4TTT 展現出最高的光電轉換效率可達1.18%,因此,更進一步比較此共軛高分子混摻碳七十衍生物做為太陽能電池主動層系統且利用加入分散劑(1,8-diiodoctane)進行加工,我們發現可以改善 P2Se4TTT 之光電轉換效率高達2.29%。綜合以上所述顯示以硒吩為基礎之噻吩共軛側鏈段系統發展之共軛高分子確實具有提升電荷傳遞的能力,是個應用於有機光電元件的明日之星。 Conjugated copolymers have attracted an extensive research interest in recent years due to their potential application on various flexible electronic devices. The intrinsic electronic and optoelectronic properties are governed by their chemical structures and morphology. In this thesis, we demonstrate the optoelectronic properties and device characterizations of donor-donor conjugated organic materials. The goals of this thesis are to address the following issues: (1) design and synthesize new donor-donor organic materials, (2) clarify the relationship within optoelectronic characterizations, thin film morphology and chemical structure, and (3) characterize the performances of organic electronics, e.g. thin film transistors, or photovoltaic cells, based on these studied materials. The objectives and the research findings are summarized as follows: 1. Synthesis and Characterization of Selenophene-Based Conjugated Polymers with Thiophene-Containing Conjugated Side Chains (Chapter 2): Five 4TSe-based conjugated copolymers, including PSe4TV, PSe4TT, PSe4T2T, PSe4TTT and P2Se4TTT with various donor-pacer structures, vinylene (V), thiophene (T), bithiophene (2T) and thienothiophene (TT) were explored. The effects of their chemical structures on the electronic energy level, thermal properties and thin film morphology were investigated. It was found that the order of the value in the band gap energy was P2Se4TTT < PSe4TTT < PSe4TV < PSe4T2T < PSe4TT. The band gap of polymer P2Se4TTT was the smallest among all the 4TSe-based polymers, owing to the inserting biselenophene which reduced the hindrance. In addition, P2Se4TTT also possessed the smallest Tg and showed fibrillar-like among of these studied copolymers, because the biselenophene with an antisymmetric structure could improve the molecular motion and packing. 2. Polymer Thin Film Transistor and Polymer Solar Cell Characteristics of Selenophene-Based Conjugated Polymers with Thiophene-Containing Conjugated Side Chain (Chapter 3): The effects of their chemical structures on the electronic energy level, charge transport and photovoltaic properties were explored systematically. Among these copolymers, the field-effect transistor based on P2Se4TTT showed the highest hole mobility up to 0.263 cm2V-1s-1 owing to its highly crystalline packing structure, and exhibited a high on/off ratio of 1.30×105, simultaneously. Furthermore, the power conversion efficiencies (PCE) of the polymer/ [6,6]-phenyl-C61-butyric acid methyl ester PC61BM photovoltaic cells were in the range of 0.43–1.18 %. In particular, the P2Se4TTT/PC71BM-based PV cells processed from an o-dichlorobenzene/1,8-diiodoctane mixed solvent showed the best PCE (2.29%) among the studied polymers. These results exhibited that 4TSe-based copolymers with conjugated side chains could enhance the charge transport characteristics and emerge as a promising candidate for organic optoelectronic devices. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/56427 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 化學工程學系 |
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