Organic field-effect transistors using liquid crystalline compound synthesized to enhance carrier-transport ability

We report the characteristics of organic field-effect transistors (OFETs) using the liquid crystalline compound synthesized to enhance carrier-transport ability. Oblique evaporation with a tilt angle of 60° and subsequent thermal annealing at 200 °C yielded anisotropic carrier transport due to the anisotropic molecular alignment. The OFETs fabricated with polymethylmethacrylate (PMMA) intermediate layers showed mobility up to 2.6 × 10−2 cm2/V s. The characteristics of OFETs depended on the deposition rate of liquid crystalline materials. The mobilities increased with decrease in the deposition rate. Polarization-resolved photoluminescence (PL) measurements exhibited that the molecular orientation in liquid crystalline films was improved with decrease in the deposition rate. Therefore it is assumed that the carrier-transport properties were enhanced by improving the molecular orientation in the liquid crystalline films.