Properties of CdSe quantum dots coated with silica fabricated in a facile way

Abstract

High quality quantum dots ( QDs) CdSe were prepared using a novel and non- TOP method. Quantum dots of different sizes ranging from 2 to 4 nm could be obtained by removing aliquots of the reaction solution at different time intervals or by adjusting some reaction conditions. The CdSe quantum dots ( core) were directly coated with silica ( shell) using a microemulsion method. The design and preparation of a model QD/ silica was described and characterized using transmission electron microscopy ( TEM), UV - vis absorption, photoluminescence and laser confocal scanning microscopy. TEM images confirmed the well- monodispersed QDs and the silica shell around the CdSe core, respectively; laser confocal microscope images, UV - vis absorption and photoluminescence spectra clearly indicated that both the original QDs and the silica- coated QDs had good fluorescence properties. The quantum dots coated with silica shells were stable, water- soluble and less toxic ( due to the silica shells), and are anticipated to be used as fluorescent probes for biosensing and imaging applications.