Oligothiophene-derivatized azobenzene as immobilized photoswitchable conjugated systems.

Immobilization of an azobenzene-bithiophene compound on a gold surface leads to self-assembled monolayers with photoswitchable electrical properties.

High on-off conductance switching ratio in optically-driven self-assembled conjugated molecular systems.

A new azobenzene-thiophene molecular switch is designed, synthesized, and used to form self-assembled monolayers (SAM) on gold. An "on/off" conductance ratio up to 7 x 10(3) (with an average value of 1.5 x 10(3)) is reported.

Structural control of the horizontal double fixation of oligothiophenes on gold.

Quaterthiophenes bearing one (1) or two (2) alkanethiol chains attached at the internal beta-position of the outermost thiophene ring through a sulfide linkage have been synthesized. Cyclic voltammetric analysis of their electrochemical behavior in solution suggests that electrooxidation of the doubly substituted oligomer 2 leads to electrodeposition of a poly(disulfide) on the anode surface. Monolayers of 1 or 2 on gold surfaces have been investigated and characterized by cyclic voltammetry, ellipsometry, contact angle measurement, and X-ray photoelectron spectroscopy.