Synthesis And Optical Properties Of Nd-sensitized NaYF₄:Yb/Nd@NaLuF₄:Yb/Er@NaYF₄:Nd@SiO₂ Multishell-structured Nanoparticles

Rare-earth doped up-conversion nanomaterials shows excellent optical properties,and have a range of application prospects in many fields such as bioimaging,clinical diagnosis and solar cells.It becomes the one of the research hotspots in the fields of materials science and chemistry.In particular,the core-shell structured upconversion nanoparticles show excellent optical properties.This strategy endows th upconvesion materials with wide applied performances by coating inert shell,active layer or multi-functional shell.Lanthanide-doped upconversion nanoparticles?UCNPs?,especially the 808nm activated UCNPs,are promising imaging agents for biological applications due to their minimal tissue overheating effects and low autofluorescence background.Here,to enhance upconverion luminescence we constructed new Nd³⁺-doped core-multishell structured nanoparticles.The NaYF₄ is chosen as host matrix for phase research.The host is synthesized nanoparticles by using thermal decomposition method.Here in core we controlled the amount Nd³⁺ions.As sensitizer and activator we chose ytterbium and erbium,respectively,and kept their concentration constantly.Next,we synthesized core-multishell NaYF₄:Yb/Nd@NaLuF₄:20Yb:2Er@NaYF₄:Nd and control its concentration to increase upconversion luminescence intensity.Also this paper adopts thermal cracking method to synthesize nanoparticles with good dispersion,high crystallinity and high-efficiency fluorescence,and then coated with surfactant CTAB and TEOS to synthesize up-conversion nanomaterials of porous SiO₂ cladding.The synthesized core-shell structure was controlled by changing the reaction conditions,and its up-conversion fluorescence properties were studied.In addition,we loaded chlorine e6?Ce6?as a photosensitizer for drug delivery,to upconversion nanoparticles?UCNPs?already coated with mesoporous silica shell.As for upconversion luminescence we proved that with coating another shell the intensity can be increased.Therefore,we chose core and shell 2 the same materials,but different concentrations.For biomedical applications recently works proved that nanoparticles under 800nm excitation have more advantages than 980nm.In this work we will properly discuss synthesis of upconverison nanoparticles and their properties under 800nm excitation the results that we get.