2003 Fiscal Year Final Research Report Summary
Syntheses of Organic n-Type Semiconductors for Field-Effect Transistors
| Project/Area Number |
14340226
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
機能・物性・材料
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| Research Institution | Okazaki National Research Institutes |
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Principal Investigator |
SUZUKI Toshiyasu Okazaki National Research Institutes, Institute for Molecular Science, Associate Professor, 分子科学研究所, 助教授 (60260030)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAMOTO Youichi Okazaki National Research Institutes, Institute for Molecular Science, Research Associate, 分子科学研究所, 助手 (80321602)
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| Project Period (FY) |
2002 – 2003
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| Keywords | transistor / device / organic semiconductor / thin film |
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| Research Abstract |
We have synthesized perfluoropentacene and perfluorotetracene as potential n-type semiconductors for organic field-effect transistors (OFETs). Perfluoropentacene and perfluorotetracene are dark blue and reddish-orange crystalline solids, respectively. The HOMO-LUMO gaps of perfluorinated acenes are smaller than those of the corresponding acenes. The reduction potential of perfluoropentacene is almost the same as that of C_<60>, which is known as an excellent n-type semiconductor for FETs. Perfluoropentacene and perfluorotetracene are planar molecules that adopt herringbone structures with the angles of 91.2° and 91.1°, respectively. The short CC contacts less than the sum of van der Waals radii were observed for both perfluorinated acenes. The interplanar distances are shorter than the layer separation of graphite, which may lead to high electron mobility along the stacking directions.
Organic field-effect transistors (OFETs) with perfluoropentacene were fabricated using top-contact geometry, and the electron mobility of 0.11 cm^2 V^<-1> s^<-1> was observed. Bipolar OFETs with perfluoropentacene and pentacene function at both negative and positive gate voltages. The improved p-n junctions are probably because of the similar d-spacings of both acenes. Complementary inverter circuits were constructed, and the transfer characteristics exhibit a sharp inversion of the output signal with a high voltage gain.
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