upconversion – TechConnect Briefs

Carcinoma cellular uptake, imaging, and targeting by RGDS- and TAT-conjugated upconversion and/or magnetic nanoparticles

Horák D., Kostiv U., Proks V., Jirák D., Institute of Macromolecular Chemistry AS CR, CZ

Specific targeting and in vivo visualization of cancer cells is of crucial importance for early detection and treatment of cancer. We have developed monodisperse poly(ethylene glycol) (PEG)-modified SiO2-coated Fe3O4 superparamagnetic nanoparticles [1] with size tuned [...]

Upconversion and White Light Generation Properties of Undoped and Yb3+ doped Yttrium Silicate Nano-Phosphors

Cinkaya H., Eryurek G., Bartolo B.D., Boston College, US

The optical systems that consist of rare earth ions embedded in a host lattice are very interesting materials for many applications such as optical sensing, data storage, nonlinear imaging and biomedical applications [1, 2, 3]. [...]

Laser precipitation of Eu and Yb codoped CaF2 nanocrystals on the surface of glass and emission characteristics

Kim D.S., Bae C-H, Lim K-S, Chungbuk National University, KR

We precipitated spatially selective Eu/Yb doped CaF2 nanocrystals on the surface of glass by CO2 laser irradiation. Because of low phonon energy of CaF2, we observed several times enhancements in down-shift emission under 365 nm [...]

Photon up-conversion and magnetic properties of rare earths-doped NaYF4 nanoparticles

García-Flores A.F., Lesseux G.G., Iwamoto W., Urbano R.R., Rettori C., Universidade Federal do ABC, BR

In this work we have investigated Yb/Er and Yb/Tm co-doped NaYF4 nanoparticles (NPs) as well as Yb and Er single doped ones by means of luminescence, high resolution transmission electron microscopy (HRTEM), X-ray powder diffraction [...]

Upconverting Nanophosphors for High Temperature Sensing Applications

Guo X., Zhao H., Song H., Chen Q., Li K.K., Zou Y.K., Jiang H., Combs C., Narayanaswamy V., Clemens N., Boston Applied Technologies, Inc., US

In this work, a unique upconverting thermographic phosphor technique was developed for overcoming the difficulties encountered currently in the down-conversion route. Upconverting nanopowders of rare earths doped refractory oxides were synthesized through a wet chemical [...]

Precipitant molar concentration effect on the upconversion emission in BaZrO3:Er,Yb nanocrystalline phosphor

Diaz-Torres L.A., Salas P., Castaño V.M., Oliva J., Angeles-Chavez C., Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, MX

Strong Blue, green, and red upconversion emission of Er3+ in sub-microcrystalline BaZrO3:(Yb3+Er3+) is observed. Powder samples were obtained by a facile hydrothermal process at 100ºC with different water to ethanol solvent ratios. The as synthesized [...]

Effects of Non-radiative energy transfer processes on the visible upconversion in ZrO2:Yb3+/Er3+ nanocrystals

Meza O., Diaz-Torres L.A., Salas P., De la Rosa E., Solis C.D., Centro de Investigaciones en Optica A C, MX

The luminescence dynamics of both near infrared (NIR) and visible (VIS) emission of Yb3+,Er3+ in nanocrystalline ZrO2 is studied. It is found that upconversion emission is dominated by back transfer processes over direct Yb to [...]

Upconverting nanoparticles for in vitro and in vivo cellular imaging

Chatterjee D.K., Zhang Y., National University of Singapore, SG

Conventional fluorescent labels are of limited in vivo utility because short-wavelength radiation penetrates tissues poorly and excites strong background autofluorescence. Upconversion nanoparticles (UCN) convert low-energy exciting photons to visible emissions, resulting in deep tissue penetration [...]

Upconverting nanoparticles for photodynamic therapy

Chatterjee D.K., Zhang Y., National University of Singapore, SG

Photodynamic therapy involves killing of diseased cells by excitation of photosensitizer chemicals with high energy light to produce cytotoxic oxygen species from surrounding dissolved oxygen. However, poor tissue penetration of high energy light and hydrophobic [...]