Enhancing the generating and collecting efficiency of single particle upconverting luminescence at low power excitation

Upconverting luminescent nanoparticles are photostable, nonblinking, and low chemically toxic fluorophores that are emerging as promising fluorescent probes at the single molecule level. High luminescence intensity upconversion nanoparticles (UCNPs) have previously been achieved by doping with high amounts of rare-earth ions using high excitation power (>2.5 MW/cm2). However, such particles are inadequate for in vitro live-cell imaging and single-particle tracking, as high excitation power can cause photodamage. Here, we compared UCNP luminescence intensities with different dopant concentrations and presented more efficient (about seven times) UCNPs at low excitation power by increasing the concentrations of Yb3+ and Tm3+ dopants (NaYF4: 60% Yb3+, 8% Tm3+) and adding a core-shell structure.

Influence of thermal treatment on photoluminescent properties of PP/PbS/CdS nanocomposites

This paper deals with an investigation on the photoluminescence (PL) properties of PP+PbS/CdS nanocomposites at different temperatures ([Formula: see text], [Formula: see text] and [Formula: see text]) under vacuum. The optical bandgap was calculated on the basis of the spectra of UV absorption and it was shown that after thermal treatment the nanocomposites optical bandgap changed. The change has been attributed to the modification of the upper molecular structure of the polymer matrix due to the thermal process. The luminescence spectra of nanocomposites before and after thermal treatment at different temperatures ([Formula: see text], [Formula: see text] and [Formula: see text]) under vacuum were also measured and discussed. A very high luminescence intensity was observed after thermal treatment at [Formula: see text] temperature. This was attributed to the luminescent centers’ increase and the optimal structure formation.

Enhancing generating and collecting efficiency of single particle upconverting luminescence at low-level power excitation

Upconverting luminescent nanoparticles are photostable, non-blinking, and low chemically toxic fluorophores that are emerging as promising fluorescent probe at single-molecule level. High luminescence intensity upconversion nanoparticles (UCNPs) is achieved with highly doped rare-earth ions co-doped (20% Yb3+) using high excitation power (>2.5 MW/cm2). However, such particles are inadequate for in-vitro live-cell imaging and single-particle tracking since high excitation power can cause photodamage. Here, we compared UCNPs luminescence intensities with different dopants concentrations and presented a more efficient (∼7x) UCNPs at low excitation power by increasing the concentrations of Yb3+ and Tm3+ dopants (NaYF4: 60% Yb3+, 8% Tm3+) and adding a core-shell structure.

Люминофор ближнего и коротковолнового ИК-диапазона на основе ниобата литий-лантана со структурой кубического граната

Cubic garnets activated by neodymium and holmium, Li_6CaLa_2Nb_2O_12:Nd^3+,Ho^3+, were obtained by solid-state method. The main regularities of changes in the luminescence properties of Li_6C-aLa_2Nb_2O_12:Nd^3+,Ho^3+ solid solutions in the visible, near-IR, and short-wave IR ranges under 808 nm laser diode radiation are determined. The energy transfer mechanism between active centers, involving the participation of Nd^3+ ions as sensitizers for the luminescence of Ho^3+ ions, is proposed. Low phonon energy, high luminescence intensity in the range of 2.0–3.0 μm, and weak up-conversion luminescence in the region of 450–780 nm make it possible to consider the cubic lithium–lanthanum niobates Li_6CaLa_2Nb_2O_12:Nd^3+,Ho^3+ as promising phosphors of the short-wave IR range.

Luminescent biomimetic citrate-coated europium-doped carbonated apatite nanoparticles for use in bioimaging: physico-chemistry and cytocompatibility

Biomimetic citrate-coated europium doped carbonated apatite nanoparticles show a high luminescence intensity and cytocompatibility for uses in cell/tissue imaging.

Photoluminescence Properties of Ru(bpy)32+ in TEMPO-Oxidized Cellulose Nanofiber Films

In this work, photoluminescent properties of Ru (bpy)32+ incorporated in cellulose nanofiber (CNF) film was investigated by comparing with those in polyvinyl alcohol (PVA) and polyacrylic acid (PAA) films. In the polymer films, the luminescence intensity of Ru (bpy)32+ was high and λmax of luminescence spectra was blue-shifted compared with those in aqueous solution. The high luminescence intensity was also observed in cellulose nanofiber (CNF) films but the spectrum was red-shifted. Luminescence decay measurement showed that the decays in polymer films were exponential and the lifetimes were far longer than that in aqueous solution. On the other hand, in CNF films, the decays were composed of fast and slow ones. The luminescence properties of Ru (bpy)32+ in CNF films were discussed based on the stabilization of excited state and the dispersibility of Ru (bpy)32+ in the films.

Long-lived photoluminescence and high quantum yield of copper(ii) complexes with novel nanostructures

Four novel nano bipy-based copper(ii) complexes with high luminescence intensity, long-lived photoluminescence and quantum yield.

Microbe-Assisted Synthesis and Luminescence Properties of Monodispersed Tb3+-Doped ZnS Nanocrystals

Tb3+-doped zinc sulfide (ZnS:Tb3+) nanocrystals were synthesized by spray precipitation with sulfate-reducing bacterial (SRB) culture at room temperature. The morphology of the SRB and ZnS:Tb3+nanocrystals was examined by scanning electron microscopy, and the ZnS:Tb3+nanocrystals were characterized by X-ray diffractometry and photoluminescence (PL) spectroscopy. The PL mechanism of ZnS:Tb3+nanocrystals was further analyzed, and the effects of Tb3+ion concentration on the luminescence properties of ZnS:Tb3+nanocrystals were studied. ZnS:Tb3+nanocrystals showed a sphalerite phase, and the prepared ZnS:Tb3+nanocrystals had high luminescence intensity under excitation at 369 nm. The main peak position of the absorption spectra positively blueshifted with increasing concentrations of Tb3+dopant. Based on the strength of the peak of the excitation and emission spectra, we inferred that the optimum concentration of the Tb3+dopant is 5 mol%. Four main emission peaks were obtained under excitation at 369 nm:489 nm (5D4→7F6), 545 nm (5D4→7F5), 594 nm (5D4→7F4), and 625 nm (5D4→7F3). Our findings suggest that nanocrystals have potential applications in photoelectronic devices and biomarkers.

Effects of Particle Size and Type of Alumina on the Morphology and Photoluminescence Properties of : Phosphor

: phosphor with high luminescence intensity and long afterglow duration was synthesized using 1.0 m (), 0.1 m (), and 0.05 m () particle sizes of . SEM observation results showed that spike-like thin particles were formed when 0.05 m - was used as raw material. Hexagonal thick particles were observed when 0.1 m - was used. But irregular, thin particles were observed while using 1 m -. Photoluminescence measurements showed that both the initial intensity and the long persistency were much higher for the phosphor prepared using - of 0.05 m particle size.