Photoelectrochemical studies of Single Walled Carbon Nanotubes Chemically modified Gold electrodes

The preparation, characterization and the unique photoelectrochemical characteristics of a gold electrode chemically modified with suitably derivatized single wall carbon nanotubes (SWCNTs) are described. The SWCNT chemically modified gold electrode (CNT-CME) was assembled by linking acid-shortened SWCNTs with carboxylic groups at the nanotube ends on a gold surface previously modified with a cysteamine monolayer. A persistent photocurrent was observed when the modified electrode was illuminated with visible light in the presence of an electroactive species (ascorbic acid AsA). The influence of physical variables (applied potential, light intensity ) and of chemical parameters (ascorbic acid concentration, pH) on the generated photocurrents were evaluated. With an appropriate applied potential this device behaved as a photodiode.