Relationship between operational stability of polymer-based organic field-effect transistors and liquid crystallinity of active layers

Abstract

To examine whether the LC nature of active layer materials is useful for obtaining polymer-based OFETs with high operational stability, OFETs with active layers of PBTTT and PCDTPT were fabricated with nearly identical device structures. Here, PBTTT and PCDTPT are LC and non-LC materials, respectively. To minimize the experimental uncertainty, their bias-stress effects were evaluated under the same bias-stress condition and vacuum environment. The PBTTT-OFETs exhibited higher stability than the PCDTPT-OFETs. However, the difference in the stability was found to be in the flat-band voltage shift, which is related not to the LC nature but to the ionization potential of the active layers. Therefore, the positive correlation between the operational stability and the LC nature could not be confirmed.