Yuhui Zheng

Emissions and photocatalytic selectivity of SrWO4:Ln3+ (Eu3+, Tb3+, Sm3+ and Dy3+) prepared by a supersonic microwave co-assistance method

The chemical effects of high intensity ultrasound and microwave irradiation on lanthanide (Eu(3+), Tb(3+), Sm(3+) and Dy(3+)) activated SrWO(4) phosphors were extensively studied. Four classes of characteristic optically active materials (red, green, orange-red and blue-yellow) with striking luminescence were facilely prepared under very low temperature (70 °C) in 45 min. Particularly, Sm(3+), Dy(3+) and Eu(3+) doped strontium tungstates were visible-light driven emissive. The photocatalytic properties of these luminescent lanthanide doped tungstates were systematically examined by investigating the degradation behavior of different dyes.

Extension of Novel Lanthanide Luminescent Mesoporous Nanostructures to Detect Fluoride

A novel polydentate type ligand derived from N(2),N(6)-bis(4,4-diethoxy-9-oxo-3-oxa-8,10-diaza-4-siladodecan-12-yl)pyridine-2,6-dicarboxamide (L) has been designed, and it played essential roles in the assembly of new organic-inorganic functional materials. First, its multiple amide groups would coordinate to lanthanide ions firmly and transfer the absorbed energy to both Eu(III) and Tb(III) simultaneously. Second, the hydrogen-bond donor units showed strong affinity to guest anion (F(-)). Third, the two silylated arms could induce the formation of sol-gel derived siloxane hybrid materials. Following this idea, two lanthanide luminescent amorphous particles (ASNs-Eu and ASNs-Tb) have been prepared for the recognition of fluoride ions. Further modification of the synthesis method and transformation to mesoporous network (MSNs-Eu and MSNs-Tb) led to much enhanced thermostabilities, larger specific surface area (from 78.5 to 515 m(2) g(-1) for Eu(III); 89.6 to 487 m(2) g(-1) for Tb(III)), and lower detection limits (2.5 × 10(-8) M for MSNs-Eu and 3.4 × 10(-8) M for MSNs-Tb) for the fluoride ion.

A luminescent lanthanide complex-based anion sensor with electron-donating methoxy groups for monitoring multiple anions in environmental and biological processes

We designed a ternary europium (III) tris(2-thenoyltrifluoroacetonate) with 2-(3,4,5-trimethoxyphenyl)imidazo[4,5-f]-1,10-phenanthroline (1) ligands for the luminescent detection of various anions, such as fluoride, acetate and dihydrogen phosphate. Characterization of the sensors photophysical properties and via NMR showed that the sensor exhibits striking emission changes to fluoride (purple), acetate (green) and dihydrogen phosphate (blue) anions, respectively. Its fluorescence lifetime was determined to be 1.10 ms for europium ions and the complex showed an overall quantum yield of 10% in DMSO. Furthermore, transparent hybrid thick films composed of the europium complex and poly-methyl methacrylate matrix were successfully prepared via copolymerization. The resulting film overall displayed intense red emissions associated with europium ions. Fluorescence microscopic evaluation showed a homogenous distribution of aggregates with average diameters of 30-50 μm throughout the film. The accordingly produced film could give rise to a luminescence change to purple in response to fluoride anions.

Novel lanthanide pH fluorescent probes based on multiple emissions and its visible-light-sensitized feature

A new type of Eu(III) ofloxacin complex as the fluorescent pH indicator has been presented. Compared to pure ligand, the complex offers more distinguished color changes (green-red-blue) derived from both lanthanide line emissions and the secondary ionization steps of ofloxacin. During the concentration dependence experiments, the photoluminescence studies on the complex showed that the excitation of this pH probe can occur at a very long wavelength which extends to visible range (Ex=427 nm). Furthermore, the functional complex was successfully incorporated into soft networks and two novel luminescent hydrogels (rod and film) were fabricated. The soft materials also exhibited specific responses towards the pH variation. Finally, the onion cell-stain experiments were carried out to further confirm the validity of pH dependence and the results support the idea that the material will be suitable for monitoring biological samples in the future.

Supersonic microwave co-assistance (SMC) efficient synthesis of red luminescent Eu3+ activated silver molybdates and their phase-dependent evolution processes

The chemical effects of high intensity ultrasound and microwave irradiation on the preparation of europium(III) activated silver molybdates were investigated and characteristic red emission was successfully achieved at a very low temperature (70 °C) in 40 minutes. X-ray powder diffraction results proved that the crystal phase of silver molybdate was heavily related to the pH value. Scanning electron microscopic images revealed rod-like structures of Ag2Mo3O10·1.8H2O and Ag2Mo2O7 were obtained in the range of pH values between 2 and 5, while growing particles of Ag2MoO4 were formed at pH values of 7 and 8. Furthermore, it has been found that the encapsulation of europium(III) in monoclinic crystal structure (Ag2Mo2O7) resulted in enhanced luminescence intensities compared to other crystal phases.

Multiple irradiation triggered the formation of luminescent LaVO4: Ln3+ nanorods and in cellulose gels

A systematic study of the preparation of lanthanide (Eu3+, Tb3+, Sm3+ and Dy3+) phosphors was carried out and luminescent materials (red, green, orange-red and blue-yellow) were successfully achieved at low temperature (70 °C) in 45 min, using simultaneous supersonic and microwave irradiation. Scanning and transmission electron microscopic images indicate that one-dimensional nanorods with diameters of 10–20 nm and lengths of up to 200 nm were formed. The phosphors were entrapped in cellulose gels and the corresponding hydrogels were also strongly emissive.

Anion Responsive Dibenzoyl‐l‐Cystine and Luminescent Lanthanide Soft Material

A mild sol–gel technique was used to incorporate terbium dibenzoyl‐l‐cystine complex into silica and green luminescent hybrid material was fabricated. 1H NMR and fluorescence spectroscopy revealed the hybrids can recognize F− anions through hydrogen bonding formation and had no sense in binding other halide or HSO4−. Furthermore, a luminescent hydrogel was successfully designed by immobilizing a terbium activated phosphor (Gd0.1Ce0.9PO4:Tb) into molecular hydrogelator (dibenzoyl‐l‐cystine). The Tb(III) emission in hydrogel media gave a distinguished enhancement based on temperature increase and the function conforms to exponential equation y = 1160.6 exp0.03x. The stability of the green luminescent gel was rather excellent and the reversibility of the gel can be recycled at least five times.

Anion/Cation (H2PO4− and Fe3+) induced dual luminescence quenching effect based on terbium solid sensor

Abstract An investigation on the photophysical properties of the newly designed terbium imidazole-4,5-dicarboxylic acid complex encapsulated in the inert matrices (tetraethoxysilane, TEOS) was performed. The composite material was very stable and showed strong green emission in pure water. Interestingly, we discovered that the luminescence of hybrid material was selectively responsive to H 2 PO 4 − . 1 H-NMR and fluorescence spectra supported that the receptor had strong affinity to dihydrogen phosphate. Meanwhile, the luminescence was quenched by Fe 3+ when adding different metal ions such as Fe 3+ , Pd 2+ , Cd 2+ , Co 2+ and Mn 2+ concomitantly. Moreover, thin film was successfully prepared by the same materials and it also exhibited selective recognition behavior to the above two ions.

Sol–Gel Electrolytes Incorporated by Lanthanide Luminescent Materials and Their Photophysical Properties

A group of silica gel electrolytes with lanthanide luminescent hybrid materials were assembled and investigated. Photophysical studies showed that terbium and europium hybrids displayed characteristic green and red emissions within the electrolytes. The influence of different concentration of the lanthanide hybrids on the electrochemical behavior of a gelled electrolyte valve-regulated lead-acid battery were studied through cyclic voltammograms, electrochemical impedance spectroscopy, water holding experiments and mobility tests. The morphology and particle size were analyzed by scanning electron microscopy. The results proved that lanthanide (Tb3+/Eu3+) luminescent materials are effective additives which will significantly improve the electrochemical properties of lead-acid batteries.

Aggregation Induced Emission Mediated Controlled Release by Using a Built-In Functionalized Nanocluster with Theranostic Features

We report biological evaluation of a novel nanoparticle delivery system based on 1,1,2-triphenyl-2-(p-hydroxyphenyl)-ethene (TPE-OH, compound 1), which has tunable aggregation-induced emission (AIE) characteristics. Compound 1 exhibited no emission in DMSO. In aqueous media, compound 1 aggregated, and luminescence was observed. The novel membrane-cytoplasm-nucleus sequential delivery strategy could induce apoptosis in four different kinds of cancer cells (including three adherent cell lines and one suspension cell line). The nanoparticles remained in the cytoplasm with intense blue emissions, whereas doxorubicin was observed in the nucleus with striking red luminescence. The nanoassembly was internalized in cells through an energy-dependent process. Three sorts of chemical inhibitors were used to clarify the endocytosis mechanism based on the AIE type prodrug. Furthermore, we have developed the first AIE theranostic system where drug targeting and release have been applied in an animal model.