Bright luminescent, colloidal stable silica coated CdSe/ZnS nanocomposite by an in situ, one-pot surface functionalization

In this article, a systematic study of the design and development of surface-modification schemes for silica coated nanocomposite via an in situ, one-pot way is presented. Silica coated CdSe/ZnS nanoparticles were prepared in a water-in-oil microemulsion and subsequently surface modified via addition of various organosilane reagents to the microemulsion system. The resulting functionalized composite nanoparticles were characterized by different techniques like Transmission Electron Microscopy (TEM), photoluminescence spectroscopy and zeta-potential measurements. The results demonstrate that depending on the sequence of addition of silica precursors and organosilanes the product can show bright luminescence or considerable colloidal stability. The organosilanes molecules which are used here, act both as a stabilizer of the microemulsion system (regarding the charge compensation) and as a functional group the final product on top of silica shell.Using these surface-modification process, silica coated nanoparticles can be more readily conjugated with biomolecules and used as highly luminescent, sensitive, and reproducible labels in bioanalytical applications. Most importantly such surface functionalization could pave the way for controlled multi-mixed nanoparticles encapsulation (for example magnetic and QD nanoparticles).

Graphical abstractAn in situ, one-pot surface functionalization has been used to synthesize bright luminescence, colloidal stable silica coated CdSe/ZnS nanocomposite.Figure optionsDownload full-size imageDownload high-quality image (130 K)Download as PowerPoint slideHighlights► Developing an in situ, one-pot preparation procedure for functionalized nanocomposites. ► Minimizing nanoparticles aggregation by introducing an optimum amount of active functional groups. ► Single or multiple nanoparticles has been coated with silica shell. ► Sequence of addition of TEOS and organosilanes has important effect on properties of final product. ► Suggesting the mechanism of producing bright luminescence or colloidal stable nanoparticles.