Hydrothermal Synthesis and Luminescence Properties of Eu²âº- and Eu³âº-Doped SrAIF5 Nanorods.

Eu²âº- and Eu³âº-doped SrAIF5 nanorods were synthesized via a hydrothermal process. The crystal structure and morphology of the final products were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The prepared nanorods' diameters range from 40 to 50 nm, and lengths range from 400 nm to 2 µm along with the doped concentration of rare earth. The f-f transitions of Eu²âº can be observed in the SrAlF5:Eu²âº nanorods at room temperature, and the photo-luminescent (PL) properties of SrAlF5:Eu³âº nanorods are also described.

Bioconjugations of polyethylenimine-capped LaF3:Ce, Tb nanoparticles with bovine serum albumin and photoluminescent properties.

Water-soluble Ce3+ and Tb3+ co-doped LaF3 nanoparticles with surfaces functionalized by a layer of polyethylenimine (PEI) were synthesized via a facile one-step hydrothermal method. Bovine serum albumin (BSA) protein was conjugated with LaF3:Ce, Tb nanoparticles via free amino groups on the surfaces of the nanocrystals. The final products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), ultraviolet (UV) spectrophotometry, and photoluminescence (PL) spectroscopy. XRD results showed that pure hexagonal phase LaF3:Ce, Tb nanoparticles could be obtained via a PEI assisted hydrothermal process at 180 degrees C for 24 h. The FE-SEM results showed that the morphology of pure LaF3:Ce, Tb nanoparticles was spherical with an average diameter of -20 nm. The UV spectra showed that BSA had been conjugated with LaF3:Ce, Tb nanoparticles. The photoluminescent (PL) properties of LaF3:Ce, Tb nanoparticles were also studied. The strong green emission of Tb3+ in LaF3:Ce, Tb nanoparticles suggests that these nanoparticles may have potential applications for labels in biological imaging and immunoassays.

Bioconjugation of poly(acrylic acid)-capped BaYF5:Yb3+/Er3+ up-conversion nanoparticles to bovine serum albumin: synthesis and photoluminescent properties.

Water-soluble BaYF5:Yb3+/Er3+ nanoparticles with the surface functionalized by a layer of poly(acrylic acid) (PAA) were synthesized via a facile one-step PAA-assisted hydrothermal method. Bovine serum albumin (BSA) protein was conjugated with BaYF5:Yb3+/Er3+ upconversion nanoparticles via free carboxylic acid groups on the surface of nanoparticles. The final products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), infrared (IR) spectrophotometry, ultraviolet (UV) spectrophotometry and photoluminescence spectroscopy (PL). The XRD results showed that PAA-capped BaYF5:Yb3+/Er3+ upconversion nanoparticles could be obtained via a PAA assisted hydrothermal process with the pH value of 8 at 200 degrees C for 24 h. The TEM results showed that the morphology of BaYF5:Yb3+/Er3+ nanoparticles was spherical particles with an average diameter of about 4 nm. The IR and UV spectra showed that BSA has been conjugated with BaYF5:Yb3+/Er3+ up-conversion nanoparticles. The luminescence properties of BaYF5:Yb3+/Er3+ up-conversion nanoparticles were also studied. The luminescence properties of the products suggest that BaYF5:Yb3+/Er3+ upconversion nanoparticles have promising applications for labels in biological assays.

PEI-capped KMgF3:Eu2+ nanoparticles for fluorescence detection of nitroaromatics in municipal wastewater.

The probing and quantitative detection of nitroaromatics is key for public safety and the monitoring of wastewater. Currently, most techniques used for the detection of nitroaromatics require ideal conditions rather than real conditions, making practical applications challenging. As nitroaromatics have strong absorption in the range of 350-370 nm, we can design a kind of KMgF3:Eu2+ nanophosphor with a strong f-f transition emission located at 362 nm, and an energy resonance transfer system based on the overlap of the emission peak of nanophosphors and the absorption peak of nitroaromatics can be constructed to realize the quantitative detection of nitroaromatics in municipal wastewater. Based on this, in this paper, a fluorescence resonance energy transfer (FRET) sensor is designed by choosing polyethylenimine (PEI)-capped KMgF3:Eu2+ nanoparticles as an energy donor for the ultrasensitive detection of nitroaromatics, which can also work as an energy acceptor. The KMgF3:Eu2+ nanoparticle sensor shows great sensitivity and selectivity and good linear characteristics in both DI water and wastewater. The detection limits in municipal wastewater were 0.456, 0.598, 0.667, 0557 and 0.678 ng/mL for TNT, TNP, p-nitrotoluene, dinitrobenzene (DNB), and nitrobenzene (NB), respectively. The detection accuracy was identified by high-performance liquid chromatography (HPLC). The results showed that the sensor had superior sensitivity and great accuracy and could be used in practical applications.

UV-vis spectral analysis of inclusion complexes between beta-cyclodextrin and aromatic/aliphatic guest molecules.

beta-Cyclodextrin (beta-CD) forms a series of supramolecular complexes with aromatic or aliphatic guest molecules such as benzaldehyde, butyl acrylate, etc. Remarkable blue shifts (lambda max) of the UV-vis absorption peaks of the guest molecules are observed after the formation of inclusion complexes. The congestion lines appearing in the guest molecules are reduced in a remarkable extent accordingly. The mechanisms of the blue shifts are investigated herein.