咔唑-噻吩共軛材料之合成、型態及應用於可溶液製程之有機場效電晶體

Syntheses, Morphologies, and Applications of Carbazole-Thiophene Conjugated Materials for Solution-Processable Organic Field-Effect Transistors

張耕培(Gung-Pei Chang)

指導教授 ： 謝國煌

國立臺灣大學/工學院/化學工程學研究所/博士(2014年)

https://doi.org/10.6342/NTU.2014.02060

摘要

本論文發展出三種具相互關聯性之有機場效應電晶體系統，從有機半導體的分子設計與合成做為元件主動層、元件製程以及元件表現進行整合探討，有機半導體的分子設計皆以咔唑(carbazole)與噻吩(thiophene)做為構築單元。
在製作電晶體元件前，所有有機半導體材料的熱性質、光學性質與電化學性質皆透過熱重分析儀、微差掃描卡計、紫外光可見光光譜儀與循環伏安儀進行完整的分析，並探討分子結構與其特性間之關係。而後將半導體材料透過溶液製程做為電晶體之薄膜主動層則以偏光顯微鏡、原子力顯微鏡與X-ray散射進行表面型態分析，以探討主動層表面型態與電晶體元件電性關係。
於本論文第二章中，製備出一系列固定共軛長度並接枝不同長度的正烷鏈取代基(咔唑-雙噻吩-咔唑，CxCzT2)之小分子，透過溶液沉積形成元件主動層後，可得到最高電洞遷移率為1.2×10-1 cm2V-1s-1。於第三章中，製備出相反共軛順序(雙噻吩-咔唑-雙噻吩，DH4T-Cz)的小分子，並且透過浸漬法製作主動層可得到最佳的電洞遷移率5×10-1 cm2V-1S-1，此系列的有機半導體可透過不同的溶液沉積技術來達到薄膜表面型態的控制，進而控制有機場效電晶體的元件表現。於第四章中，製備出兩種聚苯乙烯衍生物於側鏈帶有共軛團基(雙咔唑，PStCz2；雙噻吩-咔唑-雙噻吩，PStCzT2Cz)，並以此為新型式的高分子有機半導體作為有機場效電晶體的主動層，且透過旋轉塗佈法得到最高的電洞遷移率為1.1×10-3 cm2V-1s-1。
此三種相互關聯之有機場效應電晶體系統對於有機半導體的材料設計、元件主動層的可溶液製程以及高效能場效電晶體元件提供了經濟與低成本的概念。

關鍵字

有機場效電晶體 ； 可溶液製程 ； 咔唑 ； 噻吩 ； 高場效遷移率

並列摘要

In this thesis, three interrelated systems of solution-processable organic filed-effect transistors (OFETs) were developed from molecular design of organic semiconducting materials to their corresponding deposition techniques. The building blocks of the organic semiconductors were all based on “carbazole” and “thiophene”.
Before fabricating OFET devices, the thermal, optical, and electrochemical properties of the studied materials were fully characterized with thermogravimetric analysis, differential scanning calorimetry, ultraviolet-visible spectroscopy, and cyclic voltammetry to realize the relationships of the structure to the properties. The thin film morphologies of the studied materials as the OFET active layers were also investigated with polarizing optical microscopy, atomic force microscopy, and X-ray diffraction to realize the structural relationships to OFET performances.
In chapter 2, a series of constant conjugated backbone (carbazole-bithiophene-carbazole, CxCzT2) oligomers were prepared with various n-alkyl chain lengths. The highest FET mobility of them was in the order of 1.2×10-1 cm2V-1s-1 via solution-casting deposition. In chapter 3, an inverse conjugated backbone based on bithiophene-carbazole-bithiophene (DH4T-Cz) was prepared and yield the highest FET mobilityin the order of 5×10-1 cm2V-1S-1 via dip-coating deposition. The thin film morphologies of DH4T-Cz can be controlled via different solution deposition techniques, and yielded different OFET performances. In chapter 4, two polystyrene-derivative polymers with grafting π-conjugated moieties (bicarbazole, PStCz2; carbazole-bithiophene-carbazole, PStCzT2Cz) were prepared as a novel class of polymeric semiconductor for OFET. The highest FET mobility was in the order of 1.1×10-3 cm2V-1s-1 via spin-coating deposition.
These three interrelated developments brought economical and low-cost concepts to the molecular design of organic semiconducting materials, solution-process of OFET active layers, and high performances of OFET devices.

並列關鍵字

organic field-effect transistors ； solution process ； carbazole ； thiophene ； high field-effect mobility

參考文獻

1.6 References

[1] S.R. Forrest, Nature 428/6986 (2004) 911.

[2] G. Horowitz, Adv. Mater. 10/5 (1998) 365.

[4] C.D. Dimitrakopoulos, P.R.L. Malenfant, Adv. Mater. 14/2 (2002) 99.

[5] C.D. Dimitrakopoulos, Thin-Film Transistors (2003) 333.