Flexible ambipolar organic field-effect transistors with reverse-offset-printed silver electrodes for a complementary inverter.
We report ambipolar organic field-effect transistors and complementary inverter circuits with reverse-offset-printed (ROP) Ag electrodes fabricated on a flexible substrate. A diketopyrrolopyrrole-based co-polymer (PDPP-TAT) was used as the semiconductor and poly(methyl methacrylate) was used as the gate insulator. Considerable improvement is observed in the n-channel electrical characteristics by inserting a cesium carbonate (Cs2CO3) as the electron-injection/hole-blocking layer at the interface between the semiconductors and the electrodes. The saturation mobility values are 0.35 cm(2) V(-1) s(-1) for the p-channel and 0.027 cm(2) V(-1) s(-1) for the n-channel. A complementary inverter is demonstrated based on the ROP process, and it is selectively controlled by the insertion of Cs2CO3 onto the n-channel region via thermal evaporation. Moreover, the devices show stable operation during the mechanical bending test using tensile strains ranging from 0.05% to 0.5%. The results confirm that these devices have great potential for use in flexible and inexpensive integrated circuits over a large area.
Display and Nanosystem Laboratory, College of Engineering, Korea University, Anam-dong, Seoul 139-713, Korea. Sensor System Research Center, Korea Institute of Science and Technology, Seoul 136-791, Korea.
Junsu
J
Park
Minseok
M
Kim
Seung-Won
SW
Yeom
Hyeon Jun
HJ
Ha
Hyenggun
H
Song
Young
Y
Min Jhon
Yun-Hi
YH
Kim
Byeong-Kwon
BK
Ju