INVESTIGATION OF PHOTOINDUCED MOLECULAR SWITCHING IN A SINGLE MONOLAYER BY A DISPLACEMENT-CURRENT-MEASURING TECHNIQUE

The optical molecular switching in single monolayers containing azobenzene derivatives at the air water interface due to photoinduced cis-trans isomerization was detected by using a displacement-current-measuring technique. The reversible displacement current generation was found to be sustained by the alternative applications of ultraviolet light and visible light, whereas, the current generation was never initiated by the successive irradiation of ultravilolet or visible light. In order to clarify the physical mechanism relevant to the displacement current generation, the optical molecular switching in single monolayers deposited on solid substrates was also examined by the displacement-current-measuring technique using a (indium tin oxide)/monolayer/air-gap/(indium tin oxide) structure. As a result, the displacement-current generation from single monolayers deposited on the solid substrates was found to be initiated in a similar manner as that from monolayers formed on the water surface. Finally, we concluded that the technique developed here will be used for a better understanding of the relationship between the structure and function of monolayers and will also be used in future molecular electronic technologies.