Photoinduced self-assembly of TiO2 and SiO2 nanoparticles on sidewalls of single-walled carbon nanotubes

Abstract

Highly selective self-assembly of TiO2 and SiO2 nanoparticles (NP) on the sidewalls carbon nanotubes (SWNT) by a simple UV irradiation in aqueous media without using organic molecules were reported. SWNT were grown on Si wafers from Fe ion coated TiO2 NP catalysts by using chemical vapor deposition (CVD) method. The results show that the surface of SWNT is positively charged due to the increased hole concentration in SWNTs, which are induced by negative charges built on the underneath p-tupe Si upon UV irradiation. The NPs are not found to posses a self-assembly when the sample is not irradiated and when pH of the reaction solution is kept at 1 to alter the surface charges of NPs. The results also show that the self-assembly of TiO 2 NOs are also achieved by using externally provided NPs.