Synthesis of NaYF4:Yb3+, Er3+ upconversion nanoparticles in normal microemulsions

Abstract

An interface-controlled reaction in normal microemulsions (water/ethanol/sodium oleate/oleic acid/n-hexane) was designed to prepare NaYF4:Yb3+, Er3+ upconversion nanoparticles. The phase diagram of the system was first studied to obtain the appropriate oil-in-water microemulsions. Transmission electron microscopy and X-ray powder diffractometer measurements revealed that the as-prepared nanoparticles were spherical, monodisperse with a uniform size of 20 nm, and of cubic phase with good crystallinity. Furthermore, these nanoparticles have good dispersibility in nonpolar organic solvents and exhibit visible upconversion luminescence of orange color under continuous excitation at 980 nm. Then, a thermal treatment for the products was found to enhance the luminescence intensity. In addition, because of its inherent merit in high yielding and being economical, this synthetic method could be utilized for preparation of the UCNPs on a large scale.

Fabrication of NaYF4:Yb,Er Nanoprobes for Cell Imaging Directly by Using the Method of Hydrion Rivalry Aided by Ultrasonic

“…Acting as bio-probes, the prepared UCNPs should meet some requirements of high fluorescent intensity [ 9 , 14 ], small diameter [ 15 ], water-soluble [ 16 , 17 ], low cytotoxicity [ 15 , 18 – 21 ], etc. So, the control synthesis of UCNPs becomes to be crucial and attracts considerable interest in recent years [ 22 – 29 ]. To date, employing oleic acid (OA, C 17 H 33 COOH) to act as reaction media to obtain UCNPs with controlled size and morphology has been still a popular synthesis route [ 30 – 33 ].…”

Photocatalytic Reactivity of Carbon–Nitrogen–Sulfur-Doped TiO2 Upconversion Phosphor Composites

“…The third condition is CNS-doped TiO2 supported on NaYF4:Yb,Er, where the dotted line in the TiO2 band represents discrete energy levels imparted by C, N, or S elements. As illustrated, the upconversion phosphor as the support material contains Yb 3+ as the NIR sensitizer in the 2 F7/2 state, which transfers energy to the co-activator or Er 3+ through the 4 F7/2 and 4 I11/2 states [35,38,39]. Simultaneously, the Er 3+ emits UV-Vis-NIR photons of less than 980 nm.…”

Upconversion luminescence in BaYF5, BaGdF5 and BaLuF5 nanocrystals doped with Yb3+/Ho3+, Yb3+/Er3+ or Yb3+/Tm3+ ions

“…Much attention has been paid to upconversion phenomenon in such matrices as YF 3 , GdF 3 , LaF 3 , CaF 2 , NaYF 4 or NaGdF 4 with particular interest in bimetallic, M I M III F 4 fluorides showing exceptional properties, both morphological (high monodispersity, small size of 5 -20 nm, high crystallinity, possibility of surface modifications) and spectroscopic (bright visible emission upon excitation, stable intensity over time) [34,[47][48][49]. BaYF 5 and BaGdF 5 have been proved to be suitable hosts for upconversion nanophosphors, doped with lanthanide ion pairs mentioned before.…”