One-step synthesis of water-soluble hexagonal NaScF4:Yb/Er nanocrystals with intense red emission

Abstract

Water-soluble hexagonal NaScF4:Yb/Er nanocrystals have been directly synthesized via a facile one-step hydrothermal route. The as-prepared nanocrystals were monodisperse and could form stable colloidal solutions in polar solvents, such as water and ethanol. The novel NaScF4:Yb/Er nanocrystals exhibited intrinsic intense red upconversion emission, in contrast to other lanthanide-doped fluoride nanocrystals. Remarkably, the upconversion emission intensity was enhanced ∼6.8 times through the coating of an active-shell (containing Yb(3+)) surrounding the NaScF4:Yb/Er core nanocrystals, owing to surface passivation effect and efficient energy transfer from Yb(3+) ions in both the core and the shell to Er(3+) ions. These water-soluble hexagonal NaScF4:Yb/Er nanocrystals with intense red emission are ideal for a variety of in vitro and in vivo biological imaging applications.

Tuning the phase, morphology and size of monodisperse ScF3and NaScF4crystals through lanthanide doping

“…14,21,24 emission at 654 nm is determined to be 0.081 ms which is much longer than that at 525 nm (0.017 ms). 14,21,24 emission at 654 nm is determined to be 0.081 ms which is much longer than that at 525 nm (0.017 ms).…”

Growth of lanthanide-doped LiGdF4 nanoparticles induced by LiLuF4 core as tri-modal imaging bioprobes

“…Generally, the output UC emission intensity (I) is proportional to the pump power (P) via the following formula, I ∝ P n , where n is the number of pump photons required to populate the upper emitting level. Therefore, the slope of the luminescence intensity versus pump power in the double-logarithmic coordinate will indicate the photon number absorbed in each UCL process [13,14]. Upon excitation at 980 nm, for S8b).…”

Tunable color and energy transfer of Tm3+ and Ho3+ co-doped NaGdF4 nanoparticles

“…5 X-ray powder diffraction (XRD) data for the prepared samples (NaGdF 4 : Tm 3+ , Ho 3+ ) were taken using a Rigaku D/max-RA Xray diffractometer with Cu K α radiation (λ= 0.15406 nm) and Ni filter, operating at 20 mA, 30 kV, scanning speed, step length and diffraction range were 10 °/min, 0.1° and 10-60°, respectively. 10 The measurements of photoluminescence (PL), photoluminescence excitation (PLE) spectra and the luminescence decay curves were performed by a HITACHI F-7000 Fluorescence Spectrophotometer using a 150W Xe lamp as the excitation source, scanning at 1200 nm/min. The excitation 15 and emission slits were set to 2.5 and 5.0 nm.…”