Photocatalytic initiation of electroless deposition

Abstract

We report a one-step photocatalytically initiated electroless deposition (PIED) process that allows for the photogeneration of robust, coherent, conducting metal layers on semiconductor-sensitised insulator surfaces. The PIED process involves two steps, performed simultaneously in the same metal precursor solution: (i) Metal nanoparticles are formed at the surface of the semiconductor by photocatalytic reduction of an appropriate metal precursor. (ii) The nanoparticles then serve as nucleation centres for an autocatalytic electroless deposition process, growing and coalescing to form a continuous metal layer. Layers of various metals including Ag and Pd have been generated by PIED on mesoporous TiO 2 (m-TiO 2) coated quartz glass slides and PVDF membranes. Deposition occurs only onto areas of the substrate both sensitised with TiO 2 and irradiated with ultra-band gap energy light. The morphology of the resultant layer is dependent upon the nucleation density occurring during the primary photocatalytic stage of PIED. PIED provides a cheaper, environmentally cleaner and more controllable option than traditional techniques of plating onto dielectric surfaces.