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International Journal of Polymer Science
Volume 2012 (2012), Article ID 852063, 10 pages
http://dx.doi.org/10.1155/2012/852063
Review Article

Polysilsesquioxanes for Gate-Insulating Materials of Organic Thin-Film Transistors

1Electronic Material Research Division, Osaka Municipal Technical Research Institute, Osaka 536-8553, Japan
2JST Innovation Plaza Osaka, Osaka 594-1131, Japan
3Department of Physics and Electronics, Osaka Prefecture University, Osaka 599-8531, Japan

Received 11 August 2012; Accepted 11 September 2012

Academic Editor: Yoshiro Kaneko

Copyright © 2012 Kimihiro Matsukawa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Printable organic thin-film transistor (O-TFT) is one of the most recognized technical issues nowadays. Our recent progress on the formation of organic-inorganic hybrid thin films consists of polymethylsilsesquioxane (PMSQ), and its applications for the gate-insulating layer of O-TFTs are introduced in this paper. PMSQ synthesized in toluene solution with formic acid catalyst exhibited the electric resistivity of higher than 1014 Ω cm after thermal treatment at 150°C, and the very low concentration of residual silanol groups in PMSQ was confirmed. The PMSQ film contains no mobile ionic impurities, and this is also important property for the practical use for the gate-insulating materials. In the case of top-contact type TFT using poly(3-hexylthiophene) (P3HT) with PMSQ gate-insulating layer, the device properties were comparable with the TFTs having thermally grown SiO2 gate-insulating layer. The feasibility of PMSQ as a gate-insulating material for O-TFTs, which was fabricated on a flexible plastic substrate, has been demonstrated. Moreover, by the modification of PMSQ, further functionalities, such as surface hydrophobicity, high permittivity that allows low driving voltage, and photocurability that allows photolithography, could be appended to the PMSQ gate-insulating layers.