Characterization of self-assembled monolayers of porphyrins bearing multiple-thiol and photoelectric response

Self-assembled monolayers (SAMs) of thiol-derivatized porphyrin molecules on Au substrate have attracted extensively interest for use in sensing, optoelectronic devices and molecular electronics. In this paper, tetra-[p-(3-mercaptopropyloxy)-phenyl]-porphyrin was synthesized and self-assembled with thiol on Au substrate for porphyrin SAMs (PPS4). The electrochemical results demonstrated that PPS4 could form excellent SAMs on gold surface. Self-assembled nanojunctions of PPS4 were fabricated by using gold nanogap electrodes (gap width: ca. 100 nm). With the light on/off, the nanojunctions showed current high/low as nanometer scaled photo switch.