Optical properties of nanosized particles dispersed in colloidal solutions or arranged in 2D or 3D superlattices

Abstract

In this paper it is demonstrated that colloidal assemblies used as templates are good candidates for controlling the size and shape of nanoparticles. The optical properties of metal nanoparticles dispersed in a colloidal solution differ with size and shape. When these particles are able to self-assemble, they form monolayers in a hexagonal network or crystal with a face-centered cubic arrangement. Such self-organizations induce changes in the optical properties. The size and composition of II–VI semiconductors are controlled independently. Quantum dots are observed. For semiconductor semimagnetic nanocrystals such as Cd_1-yMn_yS, the fluorescence due to isolated Mn²⁺ ions is attributed to the aging of the particles and not to a quantum dot effect, as predicted.