Enhanced photocurrents generated by supramolecular relay/CdS-nanoparticle/ electron-donor structures on gold electrodes

An experiment was conducted to demonstrate the supramolecular organization of an electron-relay/CdS-NP/electron-donor assembly on an electrode surface. A dioctyl sulfosuccinate sodium salt (AOT)/n-heptane water-in-oil microemulsion was prepared by the solubilization of 3.5 mL distilled water in 100mL n-heptane in the presence of AOT as surfactant. The resulting mixture was separated into 60 and 40mL subvolumes. Aqueous solutions of Cd and Na₂₅ were added to the 60 and 40mL subvolumes, and then mixed and stirred for 1 hour to yield the NPs. Pyridine was then added, and the resulting precipitate was centrifuged and washed with n-heptane, petrol ether, butanol, and methanol. The organized structure enabled an electron-transfer cascade that led to effective charge separation and to efficient generation of photocurrents. It was also observed that the supramolecular association of I^-₃ to the β-CD cavity plays an important role in the generation of the photocurrent.