Probing photoinduced electron transfer reactions by in situ electrochemical contact angle measurements

摘要

In situ electrochemical static contact angle measurements are employed to probe photoinduced electron transfer processes at electrode surfaces.Photosystems consisting of tris(2,2'-bipyridyl)ruthenium(II),(Ru(bpy)_3~(2+)),N,N'-dimethyl-4,4'-bipyridinium (MV~(2+),Na_2EDTA or CdS nanoparticles,MV~(2+),triethanolamine (TEOA) were included in aqueous droplets that were coupled with a ferrocene monolayer-functionalized electrode.Upon the oxidation of the interface (0.5 V vs.Ag quasi-reference electrode),and the illumination of the systems.photoinduced electron transfer to the modified electrode proceeds.The electron transfer processes yield photocurrents,and the photoelectrochemical transformations are followed by contact angle measurements.Similarly,a CdS/bipyridnium monolayer is assembled on an Au electrode support.The redox transformations of the bipyridinium units control the hydrophilic/hydrophobic properties of the interface,and are followed by contact angle analyses.Irradiation of the CdS/bipyridinium layer associated with the electrode biased at -0.3 V yields a photocurrent.The changes in the wetting properties of the irradiated interface are investigated by contact angle measurements.