Multi-curve fitting analysis of temperature-dependent I-V curves of poly-hexathienylphenanthroline-bridged nanogap electrodes

Stable junctions were obtained by preparing polymeric hexathienylphenanthroline wires coordinated to [Ru-II(bpy)(2)](PF6)(2) groups directly in Au electrode nanogaps by electropolymerization. Reproducible nonlinear and strongly temperature-dependent curves, similar to those found for self-assembled pi-conjugated dithiols and diisocyanides inside nanoholes, were obtained rather than a tunneling behavior commonly found in alkanethiol self-assembled monolayers. This is the first time that a consistent series of data are collected for a polymer and interpreted based on a multicurve fitting method, based on the linear combination of tunneling, Frankel-Pool and hopping mechanims, indicating that various independent conduction pathways are present in the junctions.