Luminescent evolution of hybrid SiO2-coated CdTe NCs

CdTe nanocrystals (NCs) were coated with a hybrid SiO2 shell containing CdS-like clusters by a facile reflux. These hybrid SiO2-coated CdTe NCs exhibited tunable photoluminescence (PL) and high fluorescence quantum yields (QYs) up to 70% (the QY of initial CdTe NCs is 24%) due to the CdS-like cluster in the SiO2 shell nearby the CdTe core. The average fluorescence lifetime of the hybrid SiO2-coated NCs and the CdTe NCs are 36 and 25 ns, respectively. Because increased fluorescence QYs and slightly blue-shifted PL peak wavelength for these hybrid NCs were observed after the removing of TGA and Cd2+, the hybrid SiO2 shell can sufficiently passivate PL, improve chemical stability, and prevent the surface deterioration of the CdTe NCs. This is crucial for applications in biolabeling and optoelectronic devices.