Lanthanide-doped nanoparticles in sol-gel matrices; improved optical properties and new opportunities.

摘要

This thesis describes the incorporation of lanthanide-doped nanoparticles into sol-gel matrices to improve the optical properties of lanthanide ions and these materials can potentially be used in white light devices, optical amplifiers, lasers, and biolabeling. Bright white light has been generated from sol-gel thin films (SiO2 and ZrO2) made with lanthanide-doped nanoparticles through up-conversion of a single 980 nm light source. The up-conversion mechanisms involved in the generation of light has been discussed. A new and potentially efficient up-conversion process named cross-relaxation-enhanced energy-transfer (CREET) up-conversion process has been described. Preparation of semiconductor sol-gel thin films with lanthanide-doped nanoparticles has been discussed and they show energy transfer from the semiconductor matrix to the lanthanide ions. The preparation and bioconjugation of nearly monodisperse (40 nm) silica-coated LaF3:Ln3+ nanoparticles has been described.