Fabrication and optical properties of thin silica‐coated CdSe/ZnS quantum dots

We demonstrate the fabrication of thin silica‐coated CdSe/ZnS colloidal quantum dots using a reverse microemulsion method. Spherical particles of <20 nm diameter with a single dot in the centre of a thin silica shell of good morphology are achieved, promising for biophotonic applications where hydrophilic bio‐compatible and small luminescent nanoparticles are needed. We characterize the spectrally‐ and time‐resolved photoluminescence of these silica‐coated dots, from which we identify the influence of each step of the coating procedure on their emission quantum yield. Optimization of the growth parameters eventually results in a less than two‐fold reduction of the quantum yield after silica‐coating.