Significant improvement of electron mobility in organic thin-film transistors based on thiazolothiazole derivative by employing self-assembled monolayer

Abstract

n -type organic thin-film transistors based on a thiazolothiazole derivative were fabricated on a SiO2 gate insulator treated with n-alkyl self-assembled monolayers (SAMs), which were composed of various alkyl chain lengths. The field-effect electron mobility increased depending on the alkyl chain length of the SAMs. A long alkyl chain significantly improved the on current and electron mobility. The highest electron mobility of 1.2cm2∕Vs and on/off ratio of 107 were achieved with an alkyl chain longer than that of tetradecyl-trichlorosilane. This result is attributed to the suppression of the influence of electron trap sites on the SiO2 gate insulator by employing the SAM with the long alkyl chain.