新穎結晶性聚(3-已烷基噻吩)與聚(丙烯酸十八酯)之嵌段共聚高分子和摻混高分子在場效應電晶體上應用

Novel Crystalline-Crystalline Diblock Copolymers and Polymer blends of Poly(3-hexylthiophene) and Poly(Stearyl acrylate) for Field-Effect Transistors

林榮泉(Jung-Chuan Lin)

指導教授 ： 陳文章

國立臺灣大學/工學院/化學工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.02062

摘要

由於共軛嵌段共聚高分子和高分子混摻可形成奈米結構的形態，且其應用於光電元件更是備受矚目。聚(3-已烷基噻吩)是廣受研究的一種共軛高分子，因為其具有良好的光學和電學性質。然而在噻吩系硬桿柔軟嵌段共聚高分子與高分子混摻部分，其柔軟鍊段通常為非結晶性高分子。故本論文之研究目標著眼於合成新的結晶-結晶性的噻吩系硬桿柔軟嵌段共聚高分子與高分子混摻，探討其表面形態並應用於場效應電晶體。
混摻聚(3-己烷基噻吩)與聚(丙烯酸十八酯)，以溶劑溶解度誘導奈米纖維應用於場效應電晶體與型態分析(第二章)：本研究藉由混摻結晶-結晶性高分子，達到使用少量導電高分子仍然維持高效率。在不同溶解度的溶劑效應下可獲得不同的形態的薄膜。系統溶劑使用溶解度比較差的二氯甲烷時，在溶液態P3HT會形成微晶，使得在旋轉塗佈的時候P3HT先結晶並和PSA形成相分離。而使用溶解度佳的氯仿則是沒觀察到明顯的形態。另外，使用二氯甲烷當做溶劑，可以達到結晶性高分子誘導相分離並獲得高度結晶網絡狀的P3HT型態。在P3HT/PSA高分子混摻系統中，其場效應電晶體在P3HT含量只有2wt%時，載子移動率可高達3.2 × 10-3 cm2V-1s-1，與純的P3HT(3.3 × 10-3 cm2V-1s-1)擁有非常接近的電性表現，此外，混摻PSA也可以增加元件的環境穩定性。
新穎結晶結晶性聚噻吩-聚丙烯酸十八酯嵌段共聚高分子在場效應電晶體上之應用(第三章)：這部分合成三組不同PSA鏈段長度的P3HT-b-PSA，並探討不同PSA鏈段長度對於電荷傳遞和形態的影響。此新穎嵌段共聚物採原子轉移自由基聚合方式，製備不同長度之聚甲丙烯酸十八酯鏈段(重複單元為26、50與360)。在本研究中使用的SiO2有兩種，分別為未經改質的表面和經過PTS改質的表面兩種。在未經改質基材，其載子移動率隨著PSA鏈段長度增加而下降，從 3.41×10-4 cm2V-1s-1 (P1)降到2.26×10-6 cm2V-1s-1 (P3)；然而在經過PTS表面改質的基材，PSA鏈段長度增加而其載子移動率也隨之增加，從4.51×10-4 cm2V-1s-1 (P1)提升到4.16×10-3 cm2V-1s-1 (P3)。在PTS改質過的基材上，當P3HT含量為14 mol%，其有最高的載子遷移率4×10-3 cm2V-1s-1且電流開關比高達7×106，其造成不同趨勢的原因是因為表面的苯環和噻吩分子間作用力，誘使噻吩有較佳的方向性與排列性，進而形成更多的P3HT奈米纖維。本研究發現在介面自組裝層的形態對於電荷傳遞有很大的影響。

關鍵字

場效應電晶體 ； 高分子混摻 ； 嵌段共軛高分子 ； 聚(3-己烷基噻吩) ； 聚(丙烯酸十八酯)

並列摘要

Conjugated diblock copolymers or polymer blends could form nanostructured morphologies for optoelectronic device applications. Regioregular poly(3-hexylthiophene) is one of the widely studied π-conjugated polymer. However, amorphorous coil were used most of the P3HT based diblock copolymers or polymer blends for preparing nanostructured films. In this thesis, new crystalline poly(3-hexylthiophene)/poly(stearyl acrylate) polymer blends and poly(3-hexylthiophene-b-steryl acrylate) rod-coil block copolymers were explore for field-effect transistor applications, as described below.
1. Morphology and Field-Effect Transistor Characteristics of Crystalline Poly(3-hexylthiophene) and Poly(stearyl acrylate) Blends with solvent-induced Process (chapter 2): The field-effect transistors based on double-crystalline poly(3-hexylthiophene) (P3HT)/poly(stearyl acrylate) (PSA) blends system with high performance and low percolation threshold were investigated. The morphologies can be manipulated by using various solvents. In a marginal solvent of dichloromethane, the P3HT nano crystallites wires were generated in solution, but not in a good solvent of chloroform. Solvent -induced phase segregation of crystalline P3HT/PSA polymer blends provides a facile way to construct P3HT nanowires. The films prepared from CH2Cl2 tended to form well-defined nanowires with an average diameter of 30 nm, attributed to the self assembly of the P3HT segments. With decreasing the contents of P3HT, the number of the nanowires decreased significantly. The devices based on P3HT/PSA blends films with 2 wt% P3HT showed performance hole mobility of 3.2 × 10-3 cm2V-1s-1 and an excellent on/off ratio of 105-106, comparable with the homo-P3HT(3.3 × 10-3 cm2V-1s-1). Furthermore, P3HT/PSA blends with 2 wt% P3HT exhibited an excellent air stability even though exposure in air for a week, indicating the insulating crystalline PSA component plays a critical role for the improved air stability.
2. New Crystalline-Crystalline Diblock Copolymers of Poly(3-hexylthiophene-b-steryl acrylate) for Field Effect Transistors (chapter 3): The synthesis, charge transport and morphology of crystalline-crystalline diblock copolymers, poly(3-hexylthiophene-block-stearyl acrylate) (P3HT-b-PSA), with various PSA lengths are reported in this study. The new copolymers, with PSA coil lengths of 26, 50 and 360 repeating units, were synthesized by atom transfer radical polymerization (ATRP). The field-effect mobilities of P3HT-b-PSA were measured on the untreated and phenyltrichlorosilane(PTS)-treated SiO2 substrates. On the untreated SiO2 surface, the mobilities of the copolymers decreased with the increased PSA contents, from 3.41×10-4 cm2V-1s-1 (P1) to 2.26×10-6 cm2V-1s-1 (P3). In the sharp contrast, on the PTS-treated substrates, the diblock copolymers with the larger PSA content exhibited a higher mobility, from 4.51×10-4 cm2V-1s-1 (P1) to 4.16×10-3 cm2V-1s-1 (P3). The copolymers containing 14 mol% P3HT showed a good mobility of 4×10-3 cm2V-1s-1 and a high on/off ratio of 7×106 on the PTS-treated substrate. This is due to the fact that the interaction between phenyl groups and aromatic semiconducting polymers facilitated the orientation and induced the formation of more P3HT nanowires. This study provides the importance of the self-assembly monolayer at the interface for charge transport and morphology of the crystalline-crystalline diblock copolymers.

並列關鍵字

Field effect transistor ； polymer blends ； conjugated block copolymer ； Poly(3-hexylthiophene) ； Poly(Stearyl acrylate)

參考文獻

9.Lee, W. Y.; Chen, C. W.; Chueh, C. C.; Yang, C. C.; Chen, W. C., Polym. J. 2008, 40, 249-255.

14.(a) Yang, H.; Shin, T. J.; Yang, L.; Cho, K.; Ryu, C. Y.; Bao, Z., Advanced Functional Materials 2005, 15, 671-676; (b) Chang, J.-F.; Sun, B.; Breiby, D. W.; Nielsen, M. M.; Sölling, T. I.; Giles, M.; McCulloch, I.; Sirringhaus, H., Chemistry of Materials 2004, 16, 4772-4776.

62.Lee, K. H.; Kim, H. Y.; Bang, H. J.; Jung, Y. H.; Lee, S. G., Polymer 2003, 44, 4029-4034.

21.Lee, S. W.; Lee, H. J.; Choi, J. H.; Koh, W. G.; Myoung, J. M.; Hur, J. H.; Park, J. J.; Cho, J. H.; Jeong, U., Nano Letters 2009.

4.Dabirian, R.; Palermo, V.; Liscio, A.; Schwartz, E.; Otten, M. B. J.; Finlayson, C. E.; Treossi, E.; Friend, R. H.; Calestani, G.; Müllen, K.; Nolte, R. J. M.; Rowan, A. E.; Samorì, P., Journal of the American Chemical Society 2009, 131, 7055-7063.