Study on the photoinduced current in nematic liquid crystal cell with alkanethiol self-assembled monolayer

In this paper we constructed nematic liquid crystal (NLC) cells with the gold film as one substrate as well as the cells with the gold film covered with decanethiol and hexadecanethiol self-assembled monolayers (SAMs). We found the photocurrents in these three kinds of cells all increased linearly with the power of the 632.8nm illuminating beam. And the existence of alkanethiol SAM or application a high voltage could enhance the growth rate of the above linear relations. These indicated that the current originated from the light induced carrier injection from the gold electrode to NLC film, and a model of photocurrent limited by near-electrode excitons was introduced to explain the photoinduced carrier injection.