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Abstract: Six novel 8‐hydroxyquinoline derivatives were synthesized using 2‐methyl‐8‐hydroxyquinoline and para‐substituted phenol as the main starting materials, and were characterized by 1H nuclear magnetic resonance (NMR), mass spectrometry (MS), ultraviolet (UV) light analysis and infra‐red (IR) light analysis. Their complexes with Eu(III) were also prepared and characterized by elemental analysis, molar conductivity, UV light analysis, IR light analysis, and thermogravimetric–differential thermal analysis (TG–DTA). The results showed that the ligand coordinated well with Eu(III) ions and had excellent thermal stability. The structure of the target complex was EuY1–6(NO3)3.2H2O. The luminescence properties of the target complexes were investigated, the results indicated that all target complexes had favorable luminescence properties and that the introduction of an electron‐donating group could enhance the luminescence intensity of the corresponding complexes, but the addition of an electron‐withdrawing group had the opposite effect. Among all the target complexes, the methoxy‐substituted complex (–OCH3) had the highest fluorescence intensity and the nitro‐substituted complex (–NO2) had the weakest fluorescence intensity. The results showed that 8‐hydroxyquinoline derivatives had good energy transfer efficiency for the Eu(III) ion. All the target complexes had a relatively high fluorescence quantum yield. The fluorescence quantum yield of the complex EuY3(NO3)3.2H2O was highest among all target complexes and was up to 0.628. Because of excellent luminescence properties and thermal stabilities of the Eu(III) complexes, they could be used as promising candidate luminescent materials. [ABSTRACT FROM AUTHOR]

A series of terbium complexes with salicylhydrazide-salicylacylhydrazone derivatives were synthesized and characterized by elemental analysis, IR spectra, UV/vis spectra and thermal analysis. The luminescence and electrochemical properties of the terbium complexes were investigated. The results show that all the target complexes exhibited characteristic emissions of terbium ions and the complex substituted by the chlorine has the strongest luminescence intensity with the highest quantum yield at 0.609. The introduction of donating electron groups could increase the oxidation potential and the highest occupied molecular orbital energy level of the terbium complex; however, the introduction of accepting electron groups gave the opposite result. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A series of novel flavonoid derivatives and their corresponding Eu(III) and Tb(III) complexes were successfully prepared. The effect of different solvents, ligand concentrations and substituents on the luminescence intensity of ligands was studied. The results indicated that optimal luminescence concentration of the ligand was 500 μM in ethanol. The luminescence intensity of the target complexes was studied by comparing different substituents on the ligands. Among these ligands, the ligand H4 containing -Cl possessed the strongest luminescence intensity. Besides, the luminescence quantum yield of the target complexes indicated that the luminescence performance of the Tb(III) complexes was better than that of the Eu(III) complexes. [Display omitted] • A series of flavonoid ligands and their corresponding Eu(III) complexes and Tb(III) complexes were prepared. • Ligands luminescence intensity varies with ligands concentration. • Eu(III) and Tb(III) complexes emit red and green luminescence, respectively. • The effects of different substituent groups on the title complexes were compared. [ABSTRACT FROM AUTHOR]

Abstract Li+ co-doping is used as a prevalent way to improve the luminescent intensity of CeO 2 :Eu3+ [25]. Here, we investigate the structural and luminescent properties of CeO 2 :Eu3+ by the different co-doping ways of Li+ ions, including the direct co-doping of Li+ by hydro-thermal co-precipitation and the indirect co-doping of Li+ by a post calcining of Li 2 CO 3. The different co-doping ways of Li+ ions was found to cause different effect on structure and luminescence of CeO 2 :Eu3+ phosphor. The result showed opposite trend with conventional explanations [25] where the substitution of Ce4+ with doped Li+ ions are the prime reason for luminescence intensity enhancement. Oxygen vacancies should be formed due to the charge imbalance. It is found that the Li+ direct co-doped CeO 2 :Eu3+ didn't improve the crystallization of the samples due to the increase of oxygen vacancies, as is supported by X-ray diffraction(XRD) patterns and Raman spectra. Meanwhile, the spectroscopic investigations reveal that the Li+ direct co-doped CeO 2 :Eu3+ lead to less asymmetry around Eu3+ and lower luminescence. However, results show that the indirect co-doping of Li+ lead to a increase of crystallinity and decrease in oxygen vacancies concentration. The luminescent intensity of CeO 2 :Eu3+ can be significantly enhanced by indirect co-doping of Li+. Consequently, we reason that the enhanced luminescence mainly results from a increase of crystallinity and decrease in oxygen vacancies concentration due to the flux effect of Li+ ions, instead of the substitution of Ce4+ with doped Li+ ions. [ABSTRACT FROM AUTHOR]

Six new 4-acyl pyrazolone derivatives and their complexes with the terbium nitrates were synthesized and characterized by mass spectra, elemental analysis, EDTA titrimetric analysis, UV spectra, infrared spectra, molar conductivity and thermal analysis. The results showed that pyrazolone derivatives formed good coordination with the terbium ions. The introduction of electron-donating group in the ligands not only increased the luminescence intensity and fluorescence quantum yield, but also enlarged the HOMO and LUMO energy levels of corresponding terbium complexes. All the complexes possessed high luminescence intensity and showed relatively high fluorescence quantum yields. These target complexes may have vast potential to be developed as luminescence materials in the future. [ABSTRACT FROM AUTHOR]

A novel Eu 2+ –Dy 3+ co-doped strontium aluminate green long-lasting phosphors were synthesized via conventional sol–gel method with citric acid and polyethylene glycol used as chelating agent, respectively. Orthogonal experiments were employed to optimize the main synthesis conditions and obtain the optimum technological parameters. Subsequently, the crystal structure, morphology, decay curve and luminescence property of the composites were characterized. X-ray diffraction (XRD) showed that the samples were composed of single-phase SrAl 2 O 4 . Scanning electron microscopy (SEM) revealed that the resultant nanoparticles performed graininess with a size of 100 nm around. The excitation and emission spectra indicated that, excitation broadband chiefly lay in the ultraviolet range, and nanocrystalline particles emitted strong light at 510 nm, which corresponding to the typical characteristic 5d–4f transition of Eu 2+ ion excited at around 360 nm. The long afterglow photoluminescence of nanoparticles SrAl 2 O 4 : Eu 2+ , Dy 3+ (denoted as SAO: ED) was observed in the dark with the naked eye even after the removal of the excitation light. The luminescence properties suggested that SAO: ED phosphor may be regarded as a potential green phosphor candidate for near-UV and blue light-emitting diodes (LEDs). [ABSTRACT FROM AUTHOR]

Sr 2 SnO 4 :Eu3+ phosphors were prepared by a co-precipitation combined with hydrothermal method for the first time, and Li+ was introduced to improve its luminescence performance. X-ray diffraction analysis determined that Sr 2 SnO 4 :Eu3+, Li+ phosphors were successfully synthesized. The effects and mechanisms of Li+ doping on the luminescence properties of Sr 2 SnO 4 :Eu3+ were specifically discussed. At 260 nm excitation, the fluorescence spectra of the products were dominated by the 5D 0 -7F 1 characteristic emission peak of Eu3+ at 598 nm, with the electric dipole transition 5D 0 -7F 2 being distinctly lower than the magnetic dipole transition 5D 0 -7F 1 , indicating that Eu3+ selectively replaced the highly symmetrical defective sites of Sn4+. The luminous intensity and decay lifetime were significantly enhanced through co-doping Li+, which played an essential role as a charge compensator. The optimum doping concentration of Li+ was 7%. Finally, the color purity of Sr 2 SnO 4 :Eu3+, Li+ reached 99.9%, suggesting that it could be developed as a potential orange-emitting material for solid-state lighting. • Sr 2 SnO 4 :Eu3+, Li+ orange-emitting phosphors were prepared for the first time. • Eu3+ selectively replaced the defective sites of Sn4+ with high symmetry. • The luminescence performance was improved by co-doping Li+ as charge compensators. • Sr 2 SnO 4 :Eu3+, Li+ phosphors exhibited high color purity. [ABSTRACT FROM AUTHOR]

A novel BaCeF 5 : Tb3+, Eu3+ color-tunable phosphor was synthesized using a co-precipitation-hydrothermal method. The photoluminescence (PL) spectra revealed that BaCeF 5 has its own fluorescence effect as blue emission. The energy transfer process from Ce3+ to Tb3+ was achieved after doping with Tb3+, enabling the conversion of the luminous color from blue to green. By doping Eu3+ in BaCeF 5 : 10 %Tb3+, the energy transfer process from Tb3+ to Eu3+ was further realized and the transition from green to orange light continued in the phosphor. Finally, the energy transfer mechanism of Ce3+-Tb3+-Eu3+ in the BaCeF 5 : Tb3+, Eu3+ samples was explored. The results indicate that by varying the Tb3+ and Eu3+ concentrations, the phosphor transition from blue - green - orange light can be performed, which is a promising material to be applied to multicolor emission modulated luminescent materials as well as incandescent lamp materials. Modulation of the luminescence of BaCeF 5 :Tb3+,Eu3+ fluorescent nanomaterials from blue to green to orange by varying the concentration of Tb3+,Eu3+, and the energy transfer process is Ce3+→Tb3+→Eu3+. [Display omitted] [ABSTRACT FROM AUTHOR]

An abstract of the article "Synthesis and Luminescence Properties of Nine Novel Carbazolyl Diacylhydrazone Schiff-Bases" by Limin Wu and colleagues is presented.

Four novel salicylaldehyde isonicotinoyl hydrazone derivatives and their corresponding europium ion complexes were synthesized and characterized, while the luminescence properties and the fluorescence quantum yields of the target complexes were investigated. The results indicated that the ligands favored energy transfers to the emitting energy level of europium ion, and four target europium complexes showed the characteristic luminescence of central europium ion. Besides the luminescence intensity of the complex with methoxy group, which possessed the highest fluorescence quantum yield (0.522), was stronger than that of other complexes. Furthermore, the electrochemical properties of the target complexes were further investigated by cyclic voltammetry, the results indicated that the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels and the oxidation potential of the complexes with electron donating group increased, however, that of the complexes with accepting electron group decreased. [ABSTRACT FROM AUTHOR]

Six amide-based open-chain crown ether and their solid complexes with terbium nitrates were synthesized. The target complexes were characterized by elemental analysis, mass spectra, EDTA titrimetric analysis, thermal analysis, molar conductivity, infrared spectra and UV–vis spectra. Luminescence properties of the ligands and the corresponding complexes in solid were studied. The results showed that the introduction of electron-donating group to the ligand enhanced the luminescence intensity of the corresponding complex, but electron-withdrawing group conversely. Meanwhile, among all complexes, the luminescence quantum yield of the complex Tb(NO 3 ) 3 Y 1 was highest up to 0.76. Electrochemical properties were also investigated, and the results showed that the introduction of electron-donating group to the ligand enhanced the highest occupied molecular orbit (HOMO) and the lowest unoccupied molecular orbit (LUMO) energy level, but electron-withdrawing group conversely. And these target complexes may possibly be useful for studying in organic light-emitting devices field. [ABSTRACT FROM AUTHOR]

In this paper, a new blue long afterglow luminescent material CaYAl 3 O 7 :Eu2+, Dy3+ was prepared by high-temperature solid-phase method. The physical phase analysis was carried out by X-ray diffraction; the elemental valence analysis was conducted by X-ray photoelectron spectroscopy; the luminescence properties of the samples were characterized by fluorescence spectrometer and UV absorption spectrometer; and the afterglow properties were measured by afterglow spectrometer. The results show that the doping of Eu2+ and Dy3+ did not change the physical phase of the crystals. In this long afterglow material, the introduction of Dy3+ as a trap center did not change the shape of the excitation and emission spectra of the samples, but the afterglow brightness can be significantly enhanced. The best afterglow performance was achieved when the doping concentration of Dy3+was 1%, with an afterglow time of 109 min for a brightness greater than 3.2 mcd/m2 discernible to the naked eye. • A new blue long afterglow luminescent material CaYAl 3 O 7 :Eu2+, Dy3+ was prepared by high-temperature solid-phase method. • The XRD, XPS, UV-VIS, PL, PLE, afterglow and luminescence mechanism of the synthesized samples were specifically analyzed. • The afterglow performance of CaYAl 3 O 7 :Eu2+ was significantly improved by co-doping Dy3+ as a trap center. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of Schiff-base ligands and corresponding Eu(III) complexes with ligands and auxiliary ligands were prepared • Ligands possessed typical AIE characteristics in DMF/H2O solutions. • Ligands shown multiple-color emission (orange to green) due to different substituents. • Eu(III) complexes emitted red luminescence with excellent thermal stability. • Electron-donating group enhance luminescence intensity and lifetime of complexes. The organic ligands with good coordination ability to Eu(III) ion attracted great attention, but the preparation of multifunctional organic ligands with excellent performance and the potential application was still a challenge in the field of rare earth coordination. In this work, a series of Schiff-base ligands and their corresponding Eu(III) complexes were successfully prepared. The ligands L1−4 exhibited typical AIE properties with various fluorescence emissions and high fluorescence quantum yields in an aggregated state. The luminescence intensity and luminescence lifetime of Eu(III) complexes were investigated by comparing different substituents of ligands. Density functional theory (DFT) calculations suggested that the electronegativity of the ligands L1−4 changed with the change of the substituents on the salicylaldehyde, which led to the phenomenon that the ligands exhibited diverse fluorescence emission from green to orange (maximum emission wavelengths were 525 nm, 546 nm 569 nm and 582 nm, respectively). All target Eu(III) complexes exhibited red luminescence of Eu(III) ions, accompanied by outstanding thermal stability and long luminescence lifetime. The effect of various substituent groups on luminescence intensity and luminescence lifetime of complexes was ordered: EuL3(Phen)(NO 3) 3 > EuL2(Phen)(NO 3) 3 > EuL1(Phen)(NO 3) 3 > EuL4(Phen)(NO 3) 3. Based on the above results, all ligands and corresponding target Eu(III) complexes had good application prospects in the field of optical materials. [ABSTRACT FROM AUTHOR]

Novel 2-formyl-8-oxy -N- phenylacetamide quinoline derivatives shows good coordination with Eu (III) ion. The target complexes performed good thermal stability, and excellent fluorescence property. • The six novel Eu (III) complexes based on 2-formyl-8-oxy-N-phenylacetamide quinoline derivatives were prepared, and their physical and chemistry properties were proved. • Based on the photoluminescence analysis and thermogravimetric analysis, the Eu(III) complexes perform red fluorescence with a good thermal stability. • The Eu(III) complexes with -Cl group performed the best fluorescence properties because of the heavy atom effect of halogen. A series of 2-formyl-8-oxy -N- phenylacetamide quinoline derivatives ligands L1-6 were synthesized and proved by 1H NMR and MS, their corresponding Eu(III) complexes were also synthesized. Their physical and chemistry properties were proved by elemental analysis, molar conductance, UV absorption spectra, FT-IR spectra and Thermogravimetric analysis. The Eu L1-6 (NO 3) 3 ·2H 2 O preform characteristic red luminescence of Eu3+. The Eu L6 (NO 3) 3 ·2H 2 O containing Cl present the strongest luminescence intensity, as well as the fluorescence quantum yield. Based on the good thermal stability and red luminescence properties of the target Eu(III) complex, it can be designed as fluorescence probe with chemistry modification and can expand quinoline derivatives development in the field of biomedicine. [ABSTRACT FROM AUTHOR]

A new red phosphor, Bi3+ co-doped CeO 2 :Eu3+, was synthesized by a hydrothermal co-precipitation method. XRD, TEM, Raman, XPS, luminescence spectra, energy transfer mechanism, and the decay time of Bi3+ co-doped CeO 2 :Eu3+ phosphor were systematically investigated in detail. Influence of Bi3+ substitutions on Eu3+ surroundings and associated luminescence performance was researched. It is found that co-doping of Bi3+ promoted the increase of oxygen vacancies in the lattice. In addition, Bi3+-doped CeO 2 deviates the known strongly dependency of oxygen vacancies defect association energy, and Bi3+ tend to interact with oxygen vacancies at the nearest-neighbor position to inhibit the defect formation of Ce3+ oxidation states. Therefore, the presence of Bi3+ effectively enhance the emission intensity of Eu3+ under the excitation at 365 nm, even when oxygen vacancies in the lattice are increased. The results indicate that, Bi3+ co-doping effectively increases oxygen vacancies and enhances the luminescence intensity of CeO 2 :Eu3+, which promotes its potential applications in biology and medicine. Image 1 • An inversion symmetric position of Eu3+ in the CeO 2 lattice was promoted with increase of Bi3+ doping concentration. • Bi3+ substitution changed the local environment around Eu3+ and enhanced its luminescence intensity. • Study of Structure/luminescence relationship. [ABSTRACT FROM AUTHOR]