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Name (Title):
Kazuhito Tsukagoshi (Dr.), Takeo Minari (Dr.)
Affiliation:
International Center for Materials Nanoarchitectonics, NIMS
Address:
Tsukuba, Ibaraki 305-0044, Japan
Email: TSUKAGOSHI.Kazuhito@nims.go.jp
Home Page:
Presentation Title:
Selective molecular assembly for solution-based fabrication of organic field-effect transistors
Abstract:
Since the performance of organic field-effect transistors (OFETs) has reached that of
amorphous silicon based transistors, practical applications are now being expected. The
applications may stem from flexible and light-weight features of organic devices fabricated by a
solution or printing technique. We have developed a selective organization technique that allows
us simultaneous formation of organic transistor arrays from solution phase. This technique is
based on patterned functionalities on surface; difference in wettability given by the surfacemodified
materials leads the area selective crystallization of soluble organic semiconductors with
desired geometry. The self-organized organic films are extended to channels of high performance
OFETs. [1].
The self-organized formation of organic layers has been achieved by patterning self-assembled
monolayers (SAMs) on the surface of the insulating layer. The insulator surface was coated with
a SAM having an alkyl group, providing uniform hydrophobicity over the entire substrate
surface. The area that had been selected to be the channel region of the OFETs was then
irradiated with ultraviolet light through a shadow mask to remove the alkyl SAM. This area was
modified again with a SAM containing a phenyl group. The Phenyl modified surface is wettable
for organic semiconductor solutions. As a result, regions are modified to become wettable and
unwettable, by Phenyl and alkyl modifications, respectively (Fig. 1(a)). Due to the difference in
wettability on the surface, drop-casted organic semiconductor solution is attracted only into the
wettable area, which results in organic semiconductor films fully patterned on the insulator. The
self-organized organic films are extended to channels of high performance OFETs (Fig. 1(b)).
References:
T. Minari, M. Kano, T. Miyadera, S. D. Wang, Y. Aoyagi, M. Seto, T. Nemoto,
S. Isoda, and K. Tsukagoshi, Applied Physics Letters 2008, 92, 173301
86
Fig. 1 (a) Schematic of a silicon dioxide substrate patterned with two
SAMs having different wettability for the organic semiconductor
solution. (b) Arrays of organic transistors formed by the selective
organization technique. Inset shows magnified image of the
individual device. Solid line indicates the PhTS-modified area.
Poster Session PS-16