Hydrothermal Synthesis ofβ-NaYF4:Yb, Er Nanocrystals with Upconversion Fluorescence Using Tetraethylene Pentamine as Chelating Ligand

Suli Wu,Yanhui Ning,Shufen Zhang

doi:10.1155/2012/369605

Abstract

Novel chelating ligands are very significant for preparing nanocrystals with different morphologies and applications. In this paper, we directly introduced amine groups onto UCNPs by choosing a new chelating ligand tetraethylene pentamine (TEPA) to synthesisNaYF4:Yb, Er through hydrothermal method. The influences of rare earth concentration, the ratio of RE/TEPA, solvent composition, and reaction time on the morphology and fluorescence intensity of the as-preparedNaYF4:Yb, Er samples were systematically investigated and discussed. Field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), and upconversion luminescence spectroscopy were used to characterize the product. It was found that rare earth concentration, ratio of RE/TEPA, solvent composition, and reaction time were all responsible for the luminescent intensity and morphology.

Highlights

Upconversion (UC) means that the materials absorb longwaved photons to emit short-waved photons
In a typical synthesis of hexagonal phase NaYF4:Yb, Er nanocrystals, 4 mL 0.25 M 78% Y(NO3)3, 20% Yb(NO3)3, 2% Er(NO3)3 aqueous solution, 16 mL deionized water, and 20 mL ethanol were mixed with stirring at room temperature, after 0.2 mL tetraethylene pentamine (TEPA) was added into above solution, forming a A solution. 504 mg NaF was dissolved in 10 mL deionized water and 10 mL ethanol to form solution B
The morphologies of the samples were observed by using a Nova Nanosem 450 field emission scanning electron microscopy (FE-SEM)

Summary

Introduction

Upconversion (UC) means that the materials absorb longwaved photons to emit short-waved photons. The most frequently used chelating ligand was oleic acid (OA) together with a noncoordinating solvent octadecene (ODE), which controlled the nucleation and growth as well as stabilization of the crystals in a thermolysis procedure. Other chelating ligands such as oleylamine [10], octadecylamine [11], oleamide [12], trioctylphosphine (TOP) [13], and trioctylphosphine oxide (TOPO) were used to prepare NaYF4:Yb, Er [14]. We directly introduced amine groups onto UCNPs by choosing a new chelating ligand tetraethylene pentamine (TEPA) to synthesis NaYF4:Yb, Er through hydrothermal method. We can introduce other functional groups, controlling the application performance of the βNaYF4:Yb, Er nanocrystals

Experimental

Characterizations

Results and Discussion

Conclusion