| 초록 |
The effects of 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) doping on diketopyrrolo-pyrrole-based polymeric semiconductors in terms of charge transport behavior and structural ordering are systematically investigated. Ultraviolet photoelectron spectroscopy analyses revealed that a low doping ratio of 1 wt% is sufficient to tune the energy distance between the Fermi level and the HOMO level, reaching saturation at roughly 5 wt%. Structural analyses using grazing-incidence X-ray diffraction (GIXD) show that the overall degree of edge-on orientation is disturbed by the addition of dopants, with significant influence appearing at high doping ratios (＞3 wt%). The calculated charge carrier mobility from accumulation mode measurements of FETs showed a maximum value of 2 cm2/V·s at the optimized doping ratio of 1 wt%, enabled by additional holes in the channel region, which results in a roughly 40% increase relative to the undoped device. This result suggests that the electrochemical doping method can be also applied to novel donor-acceptor copolymers to further enhance their charge transport characteristics. |
