Preparation of silica encapsulated CdSe quantum dots in aqueous solution with the improved optical properties

Silica encapsulated CdSe quantum dots (QDs) have been prepared by the use of 3-mercaptopropyl trimethoxysilane (MPS) in a weak alkaline solution in ambient atmosphere at room temperature. The average size of the multicore-shell structured CdSe/SiO2 is 28.0 nm and that of the CdSe QDs is 3.4 nm from the observation of the transmission electron micrographs (TEMs). The enhanced photoluminescence (PL) intensity of the QDs has been observed by passivation of silica shell. The increased photo-chemical and -physical stability of the encapsulated CdSe/SiO2 QDs has also been demonstrated.