This work was supported by a Korea Science and Engineering Foundation (KOSEF) grant funded by the Korean government (MEST) (No. R0A-2007-000-20053-0). Supporting Information is available online from Wiley InterScience or from the author.
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Full Paper
Highly Sensitive, Photocontrolled, Organic Thin-Film Transistors Using Soluble Star-shaped Conjugated Molecules†
Article first published online: 22 SEP 2008
DOI: 10.1002/adfm.200800358
Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Additional Information
How to Cite
Cho, M. Y., Kim, S. J., Han, Y. D., Park, D. H., Kim, K. H., Choi, D. H. and Joo, J. (2008), Highly Sensitive, Photocontrolled, Organic Thin-Film Transistors Using Soluble Star-shaped Conjugated Molecules. Advanced Functional Materials, 18: 2905–2912. doi: 10.1002/adfm.200800358
- †
Publication History
- Issue published online: 6 OCT 2008
- Article first published online: 22 SEP 2008
- Manuscript Received: 13 MAR 2008
Funded by
- Korean government (MEST). Grant Number: R0A-2007-000-20053-0
Keywords:
- transistors;
- conjugated molecules;
- organic electronics;
- thin films
Graphical Abstract
The use of 4(HPBT)-benzene and 4(HP3T)-benzene, which are soluble, star-shaped, p-conjugated molecules, to fabricate highly photosensitive organic thin-film transistors is shown. Organic phototransistors based on 4(HPBT)-benzene have a high photosensitivity even with low optical powersat zero gate bias. They show a high on-off current switching ratio of ∼4 × 104 with low optical power and low gate bias.
Abstract
The highly photosensitive characteristics of organic thin-film transistors (OTFTs) made using soluble star-shaped oligothiophenes with four-armed π-conjugation paths, 4(HPBT)-benzene and 4(HP3T)-benzene molecules having a relatively high quantum yield, are reported. 4(HPBT)-benzene-based organic phototransistors (OPTs) exhibited high photosensitivity (∼2500–4300 A W−1) even with low optical powers (∼6.8–30 µW cm−2) at zero gate bias. The measured photosensitivity of the devices was much higher than that of inorganic single-crystal Si-based phototransistors, as well as that of other OPTs reported earlier. With the highly photosensitive characteristics of the 4(HPBT)-benzene-based OPTs, a high ratio of the on and off current switching of ∼4 × 104 with low optical power and low gate bias was observed. The slow relaxation of the photoinduced charges and charge-trapping phenomena at the interface could lead to a reproducible memory operation for 4(HPBT)-benzene-based OPTs.