Multifunctional MWCNTs–NaGdF4:Yb3+,Er3+,Eu3+ hybrid nanocomposites with potential dual-mode luminescence, magnetism and photothermal properties

Abstract

A novel dual-mode luminescence multifunctional hybrid nanomaterial has been successfully prepared by coating the NaGdF₄:Yb³⁺,Er³⁺,Eu³⁺ nanoparticles (NPs) on the surface of MWCNTs. The as-synthesized MWCNTs–NaGdF₄:Yb³⁺,Er³⁺,Eu³⁺ nanocomposites (NCs) can simultaneously take advantage of both magnetic and optical properties of NaGdF₄:Yb³⁺,Er³⁺,Eu³⁺ NPs and the photothermal conversion property of MWCNTs. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), vibrating sample magnetometry (VSM), UV-Vis absorption, luminescence spectroscopy and fluorescence lifetime measurements. Meanwhile, the photothermal conversion was examined under irradiation with a 980 nm laser. The results show that the MWCNTs–NaGdF₄:Yb³⁺,Er³⁺,Eu³⁺ NCs have preferably magnetic, dual-mode (up- and down-conversion) luminescence and photothermal properties. And the NCs have good biocompatibility, low toxicity and up-conversion luminescence for cell imaging. As a consequence, the dual-mode luminescence multifunctional nanomaterials have potential applications in environmental science fields and clinical fields for magnetic resonance imaging, fluorescence imaging, photothermal therapy, bioseparation and targeted drug delivery.