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.

Graphical abstractCdTe nanocrystals (NCs) were coated with a hybrid SiO2 shell containing CdS-like clusters, where the clusters resulted in the hybrid NCs with tunable photoluminescence and increased fluorescence quantum yields.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Hybrid SiO2-coated CdTe NCs were prepared by a two-step synthesis. ► The hybrid SiO2 shell contained CdS-like clusters. ► The CdS-like clusters closed the CdTe core resulted in high fluorescence QYs and red-shifted PL peak wavelength. ► The QYs of the hybrid NCs increased after the movement of TGA from solution.