Highly Sensitive,Photocontrolled, Organic Thin‐Film Transistors Using Soluble Star‐shaped Conjugated Molecules |
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Authors: | Mi Yeon Cho Su Jin Kim Yoon Deok Han Dong Hyuk Park Kyung Hwan Kim Dong Hoon Choi Jinsoo Joo |
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Affiliation: | 1. Department of Physics and Hybrid Nanostructure Lab, Korea University Seoul 136‐713 (Korea);2. Department of Chemistry, Korea University Seoul 136‐713 (Korea) |
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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. |
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Keywords: | transistors conjugated molecules organic electronics thin films |
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