Preparation and stability of strongly luminescent CdSe/Cd(OH)2/SiO2 nanocomposite particles in aqueous solution

Abstract

Cadmium hydroxide-deposited cadmium selenide nanoparticles were prepared by the addition of cadmium sulfate solution to cadmium selenide nanoparticles in a weak alkaline solution at room temperature. The photoluminescence measurements displayed that the luminescence intensity was greatly increased by the addition of cadmium ions due to the formation of cadmium hydroxide on the surfaces of the cadmium selenide nanoparticles. Then, CdSe/Cd(OH)2/SiO2 nanocomposite particles were synthesized using 3-mercatopropyl trimethoxysilane by Stober method. After the formation of CdSe/Cd(OH)2/SiO2 nanocomposite particles, the emission ability was mostly stabilized. Additionally, the stabilization of the composite particles against dilution with the physiological saline was checked. The results showed that the photoluminescence stability was promoted after the deposition of silica on the surfaces of the CdSe/Cd(OH)2 nanoparticles. Comparison of the stability of CdSe/SiO2 nanoparticles with that of CdSe/Cd(OH)2/SiO2 ones showed that Cd(OH)2 shell could enhance the photoluminescence effectively.