Optically proved molecular alignment behavior of organic semiconductor and its application for organic transistor with enhanced electrical characteristics

We systematically studied the dependence of electrical characteristics in organic field-effect transistors (OFETs) on the optically proved degree of molecular alignment. In order to control the molecular alignment behavior, we applied rubbing techniques onto a polymeric layer. With increasing the number of rubbing processes, the organic semiconducting molecules show more aligned features, and thus, higher electrical properties are obtained. In addition, we adopted a photo-elastic modulator (PEM) approach in order to prove the molecular behavior which is highly effective to analyze the molecular structure with simple experimental setup. It is concluded that the enhanced electrical properties of the OFETs originate from the multi-rubbing-induced molecular alignment of organic semiconductor.