Energy-level alignment and work function shifts for thiol-bound monolayers of conjugated molecules self-assembled on Ag, Cu, Au, and Pt

Ultraviolet photoemission spectra have been used to study the interfacial electronic structure of self-assembled monolayers of 4,4′-bis-(phenylethynyl) benzenethiol, 2-naphthalenethiol, and 3-(naphthalen-2-yl)propane-1-thiol chemisorbed on Ag, Cu, Au, and Pt. The binding energy of the highest occupied π-state and the work function of the modified surface, though dependant on the molecule, were nearly independent of the substrate.