[14a-311-1~12] 12.2 Characterization and Materials Physics

[14a-311-7] Correlation between Interfacial Structure of Ionic Liquid Electric Double Layer and Carrier Mobility of EDL-FET

Sakurako Ono¹, Hiroaki Nato¹, Kouta Sakamoto¹, Akihito Imanishi¹, Ichiro Tanabe¹, Junichi Takeya², 〇Ken-ichi Fukui¹ (1.Osaka Univ., 2.Univ. Tokyo)

Keywords:ionic liquid, field effect transistor, electric double layer

By using a combination of rubrene single crystal, which shows high hole mobility along the π-stacking row, and an ionic liquid (IL), BMIM-TFSI, for electric double layer field effect transistor (EDL-FET), we have reported that the hole mobility increased in a time scale of a day. The structural analysis of the IL/rubrene interface by electrochemical FM-AFM revealed that the rubrene gradually dissolved into IL starting from the structural defect like molecular vacancy and step, but finally the interface became completely flat forming an ideal interface. This time we used EMIM-FSI instead of BMIM-TFSI and found that the hole mobility drastically decreased in the first several hours even though the no apparent structural change was observed for the interfacial rubrene. We also found that the hole mobility is temporally recovered by applying positive gate voltage.