Effect of keto defects on the electrical properties of fluorene-based oligomers
- 저자
- Yong-Young Noh , Dong-Yu Kim, Yuji Yoshida, Kiyoshi Yase, Byung-Jun Jung, Eunhee Lim, Hong-Ku Shim and Reiko Azumi
- 저널명
- Applied Physics Letters, 85, 2953–2955 (2004)
- 년도
- 2004
- Link
- http://dx.doi.org/10.1063/1.1787939 110회 연결
The effect of ketonic defects on electrical properties, i.e., the performance of organic ®eld-effect transistors (OFETs) was examined in ¯uorene end capped fused bithiophene oligomers (BFTT). The long wavelength emission at 2.1±2.3 eV resulting from the ketonic defects was observed in photoluminescence spectra of BFTT ®lms after UV irradiation in air. In addition, the peak corresponding to the carbonyl stretching mode of the ¯uorenone moiety at 1721 cm−1 was also apparent after UV irradiation for periods longer than 6 h in air. These observations con®rm that ketonic defects are present in the ¯uorene units of BFTT after photo-oxidation. The threshold voltage sVthd, i.e., switch-on voltage, of OFETs was increased and ®eld-effect mobility smFETd was decreased after the formation of the ketonic defects, since these defects induce the formation of numerous trap sites in the bandgap of the semiconducting conjugated oligomer.