The device performance of organic thin-film transistors (OTFTs) employing the solution processed films of room temperature liquid-crystalline tetrasubstituted zinc phthalocyanine derivative was found to depend upon the film morphology. Atomic force microscopic and X-Ray diffraction studies show that the annealing at 70° produced a preferentially unidirectional void-free film with improved surface smoothness. The OTFTs with the annealed films exhibited enhanced conductivity, threefold reduction in threshold voltage, a nearly one order of magnitude increase in the on/off ratio and more than one-third reduction of hysteresis in the transfer characteristics.This work is sponsored by the Air Force Office of Scientific Research, Air Force Material Command, USAF, under grant No. FA8655-13-1-3018. TB acknowledges the financial support from the Ministry of Education and Science of the Russian Federation
