Organized mesoporous silica films as templates for the elaboration of organized nanoparticle networks

Tremendous work achieved in the last 20 years on nanoparticle synthesis has allowed us to study many new physical properties that are found in the nanometre size range. New developments are now expected when considering assemblies of nanoparticles such as 2D or 3D organized arrays. These systems are indeed expected to exhibit original physical properties resulting from particle-particle interactions. Studies in this field are clearly dependent on the elaboration of materials with controlled particle size, organization and interparticle distance. This paper presents a strategy of elaboration that is based on the use of organized mesoporous silica films as templates. These films are made by sol-gel polymerization around surfactant assemblies and further elimination of the surfactant. This provides porous matrices with a pore organization that is the almost perfect replica of the initial micellar structure. The use of such films for the elaboration of organized arrays of nanoparticles is detailed in the case of CdS and Ag particles. The formation of particles inside the pores is achieved through impregnation with precursors that are allowed to diffuse inside the pores. This leads to particles with a size and a spatial arrangement that is directly related to the initial pore structure of the films. This process opens a wide range of investigations due to the relative ease of fabrication over large surfaces and the numerous possibilities offered by the elaboration of porous films with different pore sizes and organizations.