Analysis of Single Molecule Conductance of Heterogeneous Porphyrin Arrays by Partial Transmission Probabilities

Abstract

Single molecule conductance (SMC) of a series of porphyrin derivatives, whose porphyrin units are connected through a phenylene bridge that have one or two thiolate end groups, was measured by a scanning tunneling microscopic break junction (STM-BJ) technique. The observed conductance values were analyzed by partial transmission probabilities (Ti) for the molecular parts using the equation G=G0 (Formula presented.). Unique combination of Ti was obtained, which indicates the validity of this analysis. By the analysis, the free-base porphyrin ring interacting with the gold electrode was found to show a greater transmission probability Tpor-Au than that of the bridge between thiolate and the gold electrode (TS-Au).