添加劑對富勒烯衍生物結晶行為及其場效電晶體效能之影響

Effects of Additives on the Crystallization and the Field-Effect Transistor Performance of Fullerene Derivative

姜政廷(Cheng-Ting Chiang)

指導教授 ： 童世煌

國立臺灣大學/工學院/高分子科學與工程學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202002394

摘要

本研究以PC71BM ([6,6]-phenyl-C71-butyric acid methyl ester)為半導體材料製作N型有機場效電晶體，並比較摻入不同添加劑1,8-二碘辛烷(1,8-diiodooctane, DIO)、1,8-二溴辛烷(1,8-dibromooctane, DBO)、1,8-辛二硫醇(1,8-octanedithiol, ODT)，以及對照組芐醚(benzyl ether, BE)後，電晶體電子遷移率的改變。其中DIO、DBO、ODT均為含有八個碳的長烷基添加劑，摻入PC71BM會產生特殊結晶結構，BE為不會產生任何結構之對照組，我們發現此特殊結構與元件電子遷移率的增加有相當大的關係，其中摻入莫爾比1:1 mol的添加劑 DBO可使最高電子遷移率從4.01×10-2 cm2/Vs提升到7.95×10-2 cm2/Vs。同時，我們利用光學顯微鏡(OM)、原子力顯微鏡(AFM)觀察薄膜表面形貌，確認各條件表面因素無明顯差異，以穿透式X光繞射(SAXS、WAXS)並佐以示差掃描量熱儀(DSC)分析結晶結構變化，以證明影響元件表現的主導因素為特殊結晶結構。另外從變溫結晶實驗中，得知常溫下八碳長烷基添加劑產生的結晶結構與PC71BM經過熱處理後的熱結晶並不相同，亦即添加劑誘導PC71BM產生異於自身結晶的結構，而此特殊結構即為增加電子遷移率的主要原因。

關鍵字

PC71BM ； 添加劑 ； 有機場效電晶體 ； PC71BM結晶 ； 穿透式X光繞射

並列摘要

In this study, [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) was used as a semiconductor material to fabricate N-type organic field effect transistors (OFETs). We investigated the effects of the additives with high boiling points (> 270 °C), including 1,8-diiodooctane (DIO), 1,8-dibromooctane (DBO), 1,8-octanedithiol (ODT), and benzyl ether (BE) on the packing structure of PC71BM and the performance of the OFETs. We found that the octane-based additives, DIO, DBO, and ODT, can induce PC71BM to form a crystal structure that is absent in the non-octane-based BE case. This crystal structure is highly correlated to the performance of the device. For the additives that can maintain the film uniformity of the semiconductor layers, including DBO and ODT, the electron mobilities of the devices are significantly enhanced. The highest electron mobility is 7.95×10-2 cm2/Vs for DBO at equimolar amount, increased from 4.01×10-2 cm2/Vs of pure PC71BM. The X-ray scattering techniques and differential scanning calorimetry (DSC) were used to analyze the crystal structures and the melting transitions of PC71BM, demonstrating that the crystal structure induced by the octane-based additives is different from that of pure PC71BM after thermal treatment. We suggest that this additive-induced crystal structure is the key factor contributing to the improvement of the device performance.

並列關鍵字

PC71BM ； Additive ； OFET ； Crystalline PC71BM ； X-ray Scattering

參考文獻

Yang, T.-C., M.S. thesis, National Taiwan University, 2018.

Shirakawa, H.; Louis, E. J.; MacDiarmid, A. G.; Chiang, C. K.; Heeger, A. J., Synthesis of electrically conducting organic polymers: halogen derivatives of polyacetylene, (CH). Journal of the Chemical Society, Chemical Communications Tsumura, A.; Koezuka, H.; Ando, T., Macromolecular electronic device: Field‐effect transistor with a polythiophene thin film. Applied Physics Letters 1986, 49 (18), 1210-1212.

Wang, C.; Dong, H.; Hu, W.; Liu, Y.; Zhu, D., Semiconducting π-conjugated systems in field-effect transistors: A material odyssey of organic electronics. Chemical Reviews 2012, 112 (4), 2208-2267.

Zhang, J.; Li, C. M.; Chan-Park, M. B.; Zhou, Q.; Gan, Y.; Qin, F.; Ong, B.; Chen, T., Fabrication of thin-film organic transistor on flexible substrate via ultraviolet transfer embossing. Applied Physics Letters 2007, 90 (24), 243502.

Ji, D.; Jiang, L.; Cai, X.; Dong, H.; Meng, Q.; Tian, G.; Wu, D.; Li, J.; Hu, W., Large scale, flexible organic transistor arrays and circuits based on polyimide materials. Organic Electronics 2013, 14 (10), 2528-2533.