Luminescence Lifetime Study of Ce(Ⅲ)in Ce_(0.9)RE_(0.1)P_5O_(14)Crystals

Luminescence lifetime of Ce(Ⅲ)for Ce_(0.9)RE_(0.1)P_5O_(14),where RE denotes rare earth ions other than Ce(Ⅲ), was measured by means of the time-correlated single photon counting technique.It has been found that the lifetime data are capable of elucidating the enhancement or quenching of cerium(Ⅲ)luminescence by alien RE ions(other than Ce)in doubly doped cerium pentaphosphate crystal.

Luminescent probes for luminescence lifetime sensing and imaging in live cells:a narrative review

Luminescence(mostly fluorescence and phosphorescence)probes are a powerful tool widely used in the life sciences research.They can be used,for example,in the quantitative analysis of physiological parameters,visualization of different cell organelles,and measurement of drug transportation.The luminescence intensity and lifetime of these probes are among the main signals recorded and evaluated in these applications.Other reviews have discussed optical probes from the perspective of their luminescence intensity.However,the luminescence lifetime,which depends on the molecular microenvironment but not the probe concentration,is another promising metric for biological sensing and imaging applications.In this review,we aim to introduce the basic strategies of FLIM probe design.We also present applications of these probes,including sensing of intracellular pH,cation/anion concentrations,oxygen levels,biomolecule contents,and physiological parameters,as well as live-cell imaging based on luminescence lifetime.Studies based on FLIM imaging of cells or tissues with endogenous organic molecules are not included in this mini review.With the rapid development of microscopy technology for fluorescence lifetime imaging,fluorescence lifetime-based probes have shown great potential in a variety of biological applications.

Structure and Photophysical Properties of a Chiral 4-Fold Interpenetrated Zn(Ⅱ) Coordination Polymer Tuned by 4,4'-(Hexafluoroisopropylidene)bis(benzoic acid)and 1,3-Di(pyridineyl)benzene

A new three-dimensional（3D） chiral metal-organic coordination polymer, [Zn（dpb）（hfipbb）]n, was obtained under hydrothermal conditions by 1,3-di（pyridineyl）benzene（dpb） and 4,4-（Hexafluoroisopropylidene）bis（benzoic acid）（H2hfipbb）. The as-prepared sample was characterized by single-crystal X-ray diffraction, PXRD, elemental analysis, IR spectroscopy and TGA analysis. The title coordination polymer crystallizes in orthorhombic, space group P21212, with a=21.923（4）, b=23.594（4）, c=7.3042（13） , V=3778.1（12） 3, Dc=1.209 g/cm3, Mr=687.90, F（000）=1328, μ=0.713 mm（-1） and Z=4. The compound contains two types of helical chains [Zn（hfipbb）]n and [Zn（dpb）]n which are linked with each other to generate a 3D framework by sharing the same Zn（Ⅱ） cations. It displays a 4-fold interpenetrated 3D framework. In addition, the luminescence, fluorescence lifetime and the second harmonic generation（SHG） efficiency properties in the solid state have been studied.

Luminescence of Eu^2＋ and Eu^2＋-Mn^2＋ in sodium scandium diphosphate NaScP2O7 crystal

In this work, the photoluminescence（PL） of NaScP2O7：Eu^2＋ and NaScP2O7：Eu^2＋,Mn^2＋ was investigated. Phase purity was checked using X-ray powder diffractometry（XRD）. PL excitation and emission spectra were recorded to elucidate the PL properties of NaScP2O7：Eu^2＋ and NaScP2O7：Eu^2＋,Mn^2＋. Furthermore, fluorescence lifetime measurements were performed. PL and lifetime measurements were carried out from 10 to 525 K. Moreover, the Eu^2＋ site occupation was discussed. It turned out that the incorporated Eu^2＋ ions substituted for Na＋ site and occupied two different sites. Temperature dependent PL measurements indicated the emission intensity decreased with increasing temperature due to temperature quenching in NaScP2O7：Eu^2＋. Fluorescence lifetimes of Eu^2＋ in NaScP2O7：Eu^2＋ almost did not change with a decay constant τ=~0.53 μs in the temperature range of 10–280 K, and then shortened due to temperature quenching. The luminescent lifetime reached ~0.05 μs at T=525 K. Finally, it was found that energy transfer occurred from Eu^2＋ to Mn^2＋ in co-doped NaScP2O7：Eu^2＋,Mn^2＋.

The construction of aggregation-induced charge transfer emission systems in aqueous solution directed by supramolecular strategy

Novel aggregation-induced charge transfer(CT) emission systems with long luminescence lifetime directed by supramolecular strategy have been successfully developed in water. The dimethylacridine-based electron donor(Br Ac) with excellent aggregation ability can co-aggregate with a triazine-based electron acceptor(TRZ) to form nanorods in water, which exhibit CT emission with long lifetime(τ = 0.92 μs).As for a similar electron donor(Qa Ac) with poor aggregation ability, water-soluble pillar[5]arene(WP5)can be introduced to promote the aggregation process, leading to the obvious CT emission with long lifetime(τ = 0.61 μs). In addition, structural modification of the acceptor with substituent groups possessing stronger electron-accepting capabilities will cause red-shift(about 50 nm) of the emission, which allows conveniently constructing long lifetime organic luminescent materials with different emission colors.

Luminescent properties of Tb^(3+)-doped poly(methyl methacrylate) fiber

Lanthanide-doped polymers are very attractive, since they can be used for luminescent optical fiber fabrications.This Letter presents the terbium-ions-doped poly（methyl methacrylate） fiber fabrication and spectroscopic characterization. The measured excited state（5D4） lifetime of 0.741 ms confirms that a used organometallic can be used to obtain an intense luminescence in a polymeric fiber. The luminescence spectrum shape modification versus the fiber length is also investigated.

Luminescent properties of Tm^(3+)/ Ho^(3+) co-doped LiYF_4 crystals

Ho3+ with various concentrations and Tm3+ with molar concentration of 1.28% are co-doped in Li YF4(YLF) single crystals. The luminescent properties of the crystals are investigated through emission spectra, emission cross section and decay curves under the excitation of 808 nm. The energy transfer from Tm3+ to Ho3+ and the optimum fluorescence emission of Ho3+ around 2.05 μm are investigated. The emission intensity at 2.05 μm keeps increasing with the molar concentration of Ho3+ improved from 0.50% to 1.51% when the molar concentration of Tm3+ is kept at 1.28%. Moreover, for the co-doped crystals in which the molar concentrations of Tm3+ and Ho3+ are 1.28% and 1.51%, respectively, the maximum emission cross section reaches 0.760×10–20 cm2 and the maximum fluorescence lifetime is 21.98 ms. All the parameters suggest that these materials have more advantages in the future 2.0 μm laser applications.