Intrinsically Conductive Organo–Silver Linear Chain Polymers [−S–Ag–S–Biphenyl−]_n Assembled on Roughened Elemental Silver

Abstract

A combined experimental and theoretical study of the facile polymerization of biphenyl-4,4′-dithiol (BPDT) to form intrinsically conductive linear chain [−Ag–S–BP–S−] n polymers is described. BPDT readily polymerizes and extrudes on roughened surfaces of elemental silver under ambient conditions. The self-assembled polymers can be sharply imaged through scanning electron microscopy because of their silver content and conductivity. Cyclic current versus voltage measurements (I/V curves) using a scanning tunneling microscope establish that the conductivity is intrinsic, consistent with the metallic conductivity of the linear polymer predicted through density functional theory. Systematic calculations identify that the roughness-catalyzed polymerization is driven by mobile Ag adatoms and adatom-mobilized monomers.

Isomerization of One Molecule Observed through Tip-Enhanced Raman Spectroscopy

“…In contrast with the atomically flat gold substrate, the electrochemically prepared silver tip on which the molecule appears to be, is rough. Beside heterogeneity in adsorption sites, it provides a source of mobile Ag adatoms, which we have previously shown to catalyze chemistry . Although we are left to speculate on details, the captured isomerization trajectory has all of the elements of heterogeneous chemistry in the single molecule limit.…”

“…Beside heterogeneity in adsorption sites, it provides a source of mobile Ag adatoms, which we have previously shown to catalyze chemistry. 67 Although we are left to speculate on details, the captured isomerization trajectory has all of the elements of heterogeneous chemistry in the single molecule limit. Concluding Remarks.…”