Bifunctional dual-modal luminescence nanocomposites: grafting down luminescence onto core–shell, up-conversional silica nanoarchitecture

Dual-modal luminescence nanocomposites (NCs) were successfully prepared via a facile and versatile strategy by coating the down-shifting emission (DS) ZnO quantum dots (QDs) onto core-shell NCs, in which up-conversion (UC) luminescence NaYF4:Yb3+, Er3+/Tm3+ nanoparticles (NPs) were coated by SiO2. The as-prepared NCs were characterized by X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) analysis, nitrogen adsorption-desorption isotherms and other characterization methods. Due to both their strong NIR-to-visible upconversion luminescence under 980 nm excitation and bright visible emission under UV irradiation, the dual-mode luminescent NCs are potentially useful in highly sensitive fluorescent labeling, which may attract wide attention from the fields of chemistry, materials, nanotechnology, nanobiotechnology and nanomedicine.