Photocatalytic Initiation of Electroless Deposition

Abstract

We report a one step Photocatalytically Initiated Electroless Deposition (PIED) process that allows for the photogeneration of coherent, conducting metal layers on semiconductor- sensitised insulator surfaces. Layers of silver have been generated on mesoporous TiO2 layers and nanoparticulate TiO2 coated quartz and PVDF membranes. Deposition occurs only onto areas of the substrate both sensitised with TiO2 and illuminated with light. Morphology of the resultant layer is dependant upon the nucleation density occurring during the primary photocatalytic stage of PIED. Electrogravimetry indicates that PIED results in an enhanced rate of metal nucleation on TiO2 surfaces, compared to bare metal. The mixed potential measured at TiO2-coated electrodes shifts by ~-75 - - 100 mV upon illumination during PIED, resulting in more-facile semiconductor-to-solution electron transfer, so explaining the enhanced rate of nucleation in the light. PIED provides a cheaper, environmentally cleaner and more controllable option than the traditional technique of plating onto dielectric surfaces.