Luminescent Nanoparticles of Silica‐Encapsulated Cadmium–Tellurium (CdTe) Quantum Dots with a Core–Shell Structure: Preparation and Characterization

Water‐soluble thioglycolic acid (TGA)‐capped CdTe quantum dots (QDs) were synthesized in aqueous medium, and then encapsulated in a silica nanosphere by copolymerization of the TGA‐capped CdTe conjugated with (3‐aminopropyl)triethoxysilane (APS‐CdTe conjugate), free (3‐aminopropyl)triethoxysilane (=3‐(triethoxysilyl)propan‐1‐amine; APS), and tetraethyl orthosilicate (TEOS) in a H 2 O‐in‐oil reverse microemulsion consisting of Triton X‐100 , octanol, cyclohexane, and H 2 O in the presence of aqueous NH 3 solution. The characterizations by transmission electron microscopy (TEM) and luminescence spectroscopy shows that the luminescent nanoparticles are monodisperse, spherical, and uniform in size, ca. 50 nm in diameter with a regular core–shell structure. In addition, primary amino groups directly introduced to the nanoparticle's surface by using free APS in the nanoparticle preparation enable the nanoparticles to be used easier as a biolabel. The effects of pH and metal cations on the luminescence of the nanoparticles also suggest that the new nanoparticles could be useful probes for luminescent sensings of pH and Cu 2+ ion.