Solvothermal synthesis and modification of NaYF₄:Yb/Er@NaLuF₄:Yb for enhanced up-conversion luminescence for bioimaging

Abstract

The NaYF4:Yb/Er@NaLuF4:Yb nanosphere were synthesized by a solvothermal method in a short time and low temperature, and applied to cell imaging.

Rare earth-doped nanocrystals for bioimaging in the near-infrared region

“…Li and other researchers used Lemieux–von Rudloff reagent to selectively oxidize a single unsaturated carbon–carbon double bonds to generate carboxyl groups on the surface of OA-capped nanoparticles, which not only increased the water solubility of the nanoparticles but also facilitated further biofunctional modifications. 97–99 In addition, the mixed solution of strong acid (hydrochloric or nitric acid) and nanocrystalline particles can be vigorously stirred in a low pH environment, and the oleic acid ligands on the surface of nanocrystalline particles are protonated, thereby obtaining hydrophilic rare earth-doped nanomaterials. 100,101 Lu's group used HCl solution to remove the oleate ligands on the surface of the nanoparticles, 102 and after stirring at pH 4 for 2 hours, the oleate was removed by repeated extraction with hexane, and the formed hexane layer still needed to be re-extracted with water.…”

Highly controllable and reproducible one-step synthesis of β-NaYF4:Er3+@NaYbF4@NaYF4 upconversion nanoparticles for Sb2(S,Se)3 solar cells with enhanced efficiency

“…10 With the rapid development of nanoscience, a variety of Ln-doped UCNPs have been successfully synthesized based on different routes, such as solvothermal, hydrothermal and thermal decomposition methods. 11–14 In particular, hexagonal NaYF 4 (β phase) possesses lower phonon energy than cubic NaYF 4 (α phase) and is considered one of the most efficient host materials for green/red upconversion from the combination of trivalent Yb 3+ sensitizer and Er 3+ activator under NIR excitation. 15,16…”

“…10 With the rapid development of nanoscience, a variety of Ln-doped UCNPs have been successfully synthesized based on different routes, such as solvothermal, hydrothermal and thermal decomposition methods. [11][12][13][14] In particular, hexagonal NaYF 4 (b phase) possesses lower phonon energy than cubic NaYF 4 (a phase) and is considered one of the most efficient host materials for green/red upconversion from the combination of trivalent Yb 3+ sensitizer and Er 3+ activator under NIR excitation. 15,16 However, in order to avoid concentration quenching effects, low doping concentrations of activator ions and sensitizer ions are usually adopted, 17 while surface quenching caused by surface defects and solvent adsorption cannot be ignored.…”

Exploring the use of upconversion nanoparticles in chemical and biological sensors: from surface modifications to point-of-care devices

“…When it comes to the design and preparation of crystalline upconversion materials, there are several routes to synthetize UCNPs such as co-precipitation, 19 thermal decomposition, 20 solvothermal 21 and hydrothermal 22 synthesis, and sol–gel processes. 23 Among these, one of the most used methods is thermal decomposition, which occurs at elevated temperature in high boiling point organic solvents and results in highly crystalline particles with controlled size and shape.…”