Chemistry

Free to Switch

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Science  30 May 2008:
Vol. 320, Issue 5880, pp. 1135
DOI: 10.1126/science.320.5880.1135b

In many of the reported examples of switching molecular conductivity from low to high states, conformational changes have been induced with voltage pulses from a scanning tunneling microscope (STM) tip. Such changes are highly localized and involve serial processing, whereas optically induced changes could allow for faster parallel processing. However, the quenching of excited states near metal surfaces, as well as steric constraints, often limit this approach. Kumar et al. show that azobenzene-functionalized thiol derivatives, chemisorbed within domains of decanethiol monolayers on gold, undergo reversible trans-cis photoswitching upon irradiation with ultraviolet and visible light, respectively. The exposed azobenzene group exhibits a large change in apparent height (1.4 Å) upon switching from the much more conductive trans conformation to the cis state. — PDS

Nano Lett. 8, 10.1021/nl080323+ (2008).

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