Molecular rectification: asymmetric current–voltage curves from self-assembled monolayers of a donor–(π-bridge)–acceptor dye

Abstract

Thioacetic acid S-(10-{4-[2-cyano-2-(4-dicyanomethylenecyclohexa-2,5-dienylidene)ethylidene]-4H-quinolin-1-yl}decyl) ester (1a) forms self-assembled monolayers on gold with loss of the acetyl group, the thickness and contact area being 2.25 ± 0.05 nm and 0.36 ± 0.03 nm² molecule⁻¹ respectively. The films exhibit asymmetric current–voltage characteristics, which have been unambiguously assigned to molecular rectification.