Low-voltage, high-performance n-channel organic thin-film transistors based on tantalum pentoxide insulator modified by polar polymers
✍ Scribed by Linfeng Lan; Junbiao Peng; Mingliang Sun; Jianlin Zhou; Jianhua Zou; Jian Wang; Yong Cao
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 512 KB
- Volume
- 10
- Category
- Article
- ISSN
- 1566-1199
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✦ Synopsis
Polar polymers (polyfluorene copolymers, PFN-PBT) with different polarities are utilized to modify the surface of tantalum pentoxide (Ta 2 O 5 ) insulator in n-channel organic thin-film transistors (OTFTs). A high mobility of 0.55 cm 2 /Vs, high on/off current ratio of 1.7 Â 10 5 , and low threshold voltage of 2.8 V are attained for the OTFT with the modification polymers, the performances of which are much better than those of OTFT with only Ta 2 O 5 insulator. The performances of the OTFT with only Ta 2 O 5 insulator are only 0.006 cm 2 /Vs in mobility, 5 Â 10 3 in on/off ratio, and 12.5 V in threshold voltage. Furthermore, it is found that the threshold voltage of the OTFTs with PFN-PBT modification layer is easily tuned by polarities of the polymers. Further studies show that self-assembly dipole moments in the polymers play an important role in the improvement of the OTFT performances.