噻吩系列和萘雙亞醯胺系列共軛高分子於異質結光電元件應用

Synthesis of P-type thiophene-based and N-type naphthalenediimide-based conjugated polymers for heterojunction applications in optoelectronic devices

吳穎昇(Ying-Sheng Wu)

指導教授 ： 闕居振

國立臺灣大學/工學院/化學工程學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202003471

摘要

有機共軛高分子因其製程低廉、可大面積製造且運用於溶液製程的特性，且於機械性質上可撓曲特性等優點而廣泛應用於場效電晶體、太陽能電池與記憶體等電子元件上。也因此，隨著有機合成學科於近幾年的日新月異下，可導電的高分子結構也漸漸地引起了重視。本論文目標在於合成出噻吩系列和萘雙亞醯胺系列的高分子衍生物，系統性的探討其結構設計對於高分子薄膜型態與光電特性之間的關聯以及影響。
本文的第一部分 (第二章)，噻吩系列共軛高分子衍生物的應用。著名的噻吩系列共軛高分子P3HT，為人詬病的就是其不佳的載子遷移率以及拉伸性，而為了改善其載子遷移率以及拉伸性，我們合成了帶有酯基的側鍊(PDCTT)以及雙軸延伸(PDCTT2T)的共軛高分子，以及對其分別引入了氟基團。而做了如此改質的這四隻共軛高分子也確實比P3HT擁有更好的載子遷移率。而由於多了雙軸上的延伸，會使得PDCTT2T較PDCTT系列擁有更長的堆疊距離。此項原因大大的影響到高分子於拉伸狀態下的表現。帶有氟基團的主鍊會較沒有氟基團的主鍊來的硬，也因此會有較強的分子間作用力。上述原因都是我們於本文中會去探討共軛高分子在結構設計上與載子遷移率以及拉伸性的關係。
本文的第二部分 (第三章)，萘雙亞醯胺系列共軛高分子衍生物的應用。NDI系列是非常有名的N-type材料，而N-type材料目前於學術界上是較缺乏研究的。因此本文著重在對於NDI系列作一系列的結構設計以及簡單的改質，包括引入了使其排列性較佳的矽鍊，以及可以增強其分子內作用力的硒吩，並採用了與P-type材料不同的A1-D-A2-D設計，希望可以藉由結構設計來合成出一系列值得探討的N-type材料，而本章節目前只截至合成的部分，物性鑑定會於未來完成。

關鍵字

噻吩高分子 ； 酯基 ； 雙軸延伸 ； 氟化結構 ； 拉伸性 ； 場效電晶體

並列摘要

Due to the advantages of low cost, massive production and solubility, organic conjugated polymers are widely used in optoelectronic applications. Also, as the progression of organic synthesis, conductive structures are receiving more and more attention. The goal of this thesis is to synthesize thiophene based and naphthalenediimide based polymers, and systematically exploring the relationship between structure and its chemical, physical properties.

1. Ester-Substituted, Biaxially Extended Conjugated Side-Chain Polythiophene
In chapter 2, to improve the mobility and stretchability of polythiophene derivatives, the ester-substituted biaxial-extended conjugated side-chain was installed on polymers backbones with thieno[3,2-b]thiophene and fluorinated/non-fluorinated dithiophene derivatives. Four studied polymers, including PDCTT/-F and PDCTT-2T/-F were investigated. PDCTT-F. PDCTT/-F and PDCTT-2T/-F exhibit μhs of 0.32/0.054, 0.15/0.20 m2 V−1 s−1, which are much higher than FET mobility of P3HT in reported literatures (lower than 0.014 cm2 V−1 s−1). In terms of solid-state morphology, PDCTT-2T/-F have longer packing distance while higher elastic modulus than PDCTT/-F due to the extended conjugation on side-chain. These property differences greatly affected the behavior of polymers films under stretched state. These findings elucidate the importance of rigidified backbone that ensures the stretchability and mobility of polymers with biaxial extension by maintaining efficient in-chain charge transport, and become an emerging strategy to improve the mobility and stretchability of polythiophene derivatives.

2. Naphthalenediimide-Based Polymers
Naphthalenediimide series are very famous N-type materials, however n-type materials comparing to p-type materials still lack researching. Thus, in Chapter 3, naphthalenediimide will be synthesized by making some difference such as changing alkyl side chains into silane substituted side chains, replacing thiophene by selenophene which enables the enhancement of intramolecular force, at last we change the normal p-type D-A design into A1-D-A2-D configuration, we hope by novel synthesis strategy, a series of worth studying n-type materials can be synthesized. However, this chapter only includes synthesis part, characteristic will be done in the near future.

並列關鍵字

thiophene-based polymers ； carboxylated group ； biaxially extension ； fluorination ； stretchable ； transistor

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