Energy transfer and tunable luminescence properties of Eu3+ in TbBO3 microspheres via a facile hydrothermal process

Tb(1-x)BO3:xEu(3+) (x = 0-1) microsphere phosphors have been successfully prepared by a simple hydrothermal process directly without further sintering treatment. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), photoluminescence (PL), low-voltage cathodoluminescence (CL), and time-resolved emission spectra as well as lifetimes were used to characterize the samples.

Bluish-white emission from radical carbonyl impurities in amorphous Al2O3 prepared via the Pechini-type sol-gel process

Many efforts have been devoted to exploring novel luminescent materials that do not contain expensive or toxic elements, or do not need mercury vapor plasma as the excitation source. In this paper, amorphous Al2O3 powder samples were prepared via the Pechini-type sol-gel process. The resulting samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), photoluminescence (PL) excitation and emission spectra, kinetic decay, and electron paramagnetic resonance (EPR).

Solvothermal synthesis of well-dispersed MF2 (M = Ca, Sr, Ba) nanocrystals and their optical properties

MF2 (M = Ca, Sr, Ba) nanocrystals (NCs) were synthesized via a solvothermal process in the presence of oleic acid and characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectra, UV/vis absorption spectra, photoluminescence (PL) excitation and emission spectra, and lifetimes, respectively. In the synthetic process, oleic acid as a surfactant played a crucial role in confining the growth and solubility of the MF2 NCs. The as-prepared CaF2, SrF2 and BaF2 NCs present morphologies of truncated octahedron, cube and sheet in a narrow distribution, respectively.

Hydrothermal synthesis and luminescent properties of LuBO3: Tb3+ microflowers

Hexagonal vaterite-type LuBO3:Tb3+ microflower-like phosphors have been successfully prepared by an efficient surfactant- and template-free hydrothermal process directly without further sintering treatment. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectrometry transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), photoluminescence(PL) and cathodoluminescence (CL) spectra as well as kinetic decays were used to characterize the samples.

Theoretical studies on electronic structures, spectra and charge transporting properties of a series of Pt((CN)-N-Lambda)(2) complexes

We report a quantum-chemical study of electronic, optical and charge transporting properties of four platinum (II) complexes, pt((CN)-N-Lambda)(2) ((CN)-N-Lambda=phenylpyridine or thiophenepyridine). The lowest-lying absorptions at 442, 440, 447 and 429 nm are all attributed to the mixed transition characters of metal-to-ligand charge transfer (MLCT) and ligand-centered (LC) pi - pi(*) transition. While, unexpectedly, the lowest-lying phosphorescent emissions at 663, 660, 675 and 742 nm are mainly from metal-to-ligand charge transfer ((MLCT)-M-3) ligand-centered (LC) pi ->pi* transition. Ionization potential (IP), electron affinities (EA) and reorganization energy P (lambda(hole/electron)) were obtained to evaluate the charge transfer and balance properties between hole and electron.

Tm3+ and/or Dy3+ doped LaOCl nanocrystalline phosphors for field emission displays

Blue, yellow and white light emissive LaOCl:Tm3+, LaOCl:Dy3+ and LaOCl: Tm3+, Dy3+ nanocrystalline phosphors were synthesized through the Pechini-type sol-gel process. X-Ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), photoluminescence (PL) and cathodoluminescence (CL) spectra were used to characterize the samples. Under UV radiation (229 nm) and low-voltage electron beam (0.5-5 kV) excitation, the Tm3+-doped LaOCl phosphor shows a very strong blue emission corresponding to the characteristic transitions of Tm3+ (D-1(2), (1)G(4) -> F-3(4), H-3(6)) with the strongest emission at 458 nm. The cathodoluminescent color of LaOCl:Tm3+ is blue to the naked eye with CIE coordinates of x = 0.1492, y = 0.0684. This phosphor has better CIE coordinates and higher emission intensity than the commercial product Y2SiO5:Ce3+.

One-dimensional CaWO4 and CaWO4:Tb3+ nanowires and nanotubes: electrospinning preparation and luminescent properties

One-dimensional CaWO4 and CaWO4:Tb3+ nanowires and nanotubes have been prepared by a combination method of sol-gel process and electrospinning. X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL), low voltage cathodoluminescence (CL) and time-resolved emission spectra, as well as kinetic decays were used to characterize the resulting samples. The results of XRD, FT-IR, TG-DTA indicate that the CaWO4 and CaWO4: Tb3+ samples begin to crystallize at 500 degrees C with the scheelite structure. Under ultraviolet excitation and low-voltage electron beams excitation, the CaWO4 samples exhibit a blue emission band with a maximum at 416 nm originating from the WO42- groups, while the CaWO4:Tb3+ samples show the characteristic emission of Tb3+ corresponding to (D4-F6,5,4,3)-D-5-F-7 transitions due to an efficient energy transfer from WO42- to Tb3+.

One-Dimensional Ce3+- and/or Tb3+-Doped X-1-Y2SiO5 Nanofibers and Microbelts: Electrospinning Preparation and Luminescent Properties

One-dimensional X-1-Y2SiO5:Ce3+ and -Tb3+ nanofibers and quasi-one-dimensional X-1-Y2SiO5:Ce3+ and -Tb3+ microbelts have been prepared by a simple and cost-effective electrospinning process. X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry, transmission electron microscopy, high-resolution transmission electron microscopy, photoluminescence (PL), and cathodoluminescence spectra were used to characterize the samples. SEM results indicate that the as-prepared fibers and belts are smooth and uniform with a length of several tens to hundreds of micrometers, whose diameters decrease after being annealed at 1000 degrees C for 3 h. Under ultraviolet excitation and low-voltage electron beam excitation, the doped rare earth ions show their characteristic emission, that is, Ce3+ 5d-4f and Tb3+ D-5(4)-F-7(J) (J = 6, 5 4, 3) transitions, respectively.

Structural and Bluish-White Luminescent Properties of Li+-Doped BPO4 as a Potential Environmentally Friendly Phosphor Material

Many efforts have been devoted to exploring novel luminescent materials that not contain expensive or toxic elements, or do not need a mercury vapor plasma source. In this paper, BPO4 and Li+-doped BPO4 powder samples were prepared by the Pechini-type sol-gel (PSG) process. The structure and optical properties of the resulting samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), photoluminescence (PL) excitation and emission spectra, kinetic decay, and X-ray photoelectron spectra (XPS), respectively. It was found that PSG -derived Li+-doped BPO4 annealed at 960 degrees C exhibited bright bluish-white emission centered at 416 nm. The luminescence decay curves analysis indicates that each sample has two kinds of lifetimes (5.9 ns and 0.529 ms) and two types of kinetic decay behaviors which can be fitted into a single-exponential function and a double-exponential function, respectively.

Synthesis and characterization of monodisperse spherical SiO2@RE2O3 (RE = rare earth elements) and SiO2@Gd2O3:Ln(3+) (Ln = Eu, Tb, Dy, Sm, Er, Ho) particles with core-shell structure

Spherical SiO2 particles have been coated with rare earth oxide layers by a Pechini sol-gel process, leading to the formation of core-shell structured SiO2@RE2O3 (RE = rare earth elements) and SiO2@Gd2O3:Ln(3+) (Ln = Eu, Tb, Dy, Sm, Er, Ho) particles. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence (PL), and cathodoluminescence spectra as well as lifetimes were used to characterize the resulting SiO2@RE2O3 (RE = rare earth elements) and SiO2@Gd2O3:Ln(3+) (Eu3+, Tb3+, Dy3+, Sm3+, Er3+, Ho3+) samples. The obtained core-shell phosphors have perfect spherical shape with narrow size distribution (average size ca. 380 nm), smooth surface and non-agglomeration. The thickness of shells could be easily controlled by changing the number of deposition cycles (40 nm for two deposition cycles).

Preparation and luminescence properties of Ce3+ and/or Tb3+ doped LaPO4 nanofibers and microbelts by electrospinning

Ce3+ and/or Tb3+ doped LaPO4 nanofibers and microbelts have been prepared by a combination method of sol-gel process and electrospinning. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL), low voltage cathodoluminescence (CL) and time-resolved emission spectra as well as kinetic decays were used to characterize the resulting samples. SEM and TEM results indicate the as-formed precursor fibers and belts are smooth. and the as-prepared nanofibers and microbelts consist of nanoparticles. The doped rare-earth ions show their characteristic emission under ultraviolet excitation, i.e. Ce3+ 5d-4f and Tb3+ D-5(4)-F-7(j) (J = 6-3) transitions, respectively. The energy transfer process from Ce3+ to Tb3+ in LaPO4:Ce3+, Tb3+ nanofibers was further studied by the time-resolved emission spectra.

Preparation and luminescence properties of Mn2+-doped ZnGa2O4 nanofibers via electrospinning process

One-dimensional Mn2+-doped ZnGa2O4 nanofibers were prepared by a simple and cost-effective electrospinning process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), energy-dispersive X-ray spectrum (EDS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL) and cathodoluminescence (CL) spectra as well as kinetic decays were used to characterize the samples. SEM results indicated that the as-formed precursor fibers and those annealed at 700 degrees C are uniform with length of several tens to hundred micrometers, and the diameters of the fibers decrease greatly after being heated at 700 degrees C. Under ultraviolet excitation (246 nm) and low-voltage electron beams (1-3 kV) excitation, the ZnGa2O4:Mn2+ nanofibers presents the blue emission band of the ZnGa2O4 host lattice and the strong green emission with a peak at 505 nm corresponding to the T-4(1)-(6)A(1) transition of Mn2+ ion.

Hydrothermal synthesis and luminescent properties of Y2O3:Tb3+ and Gd2O3:Tb3+ microrods

One-dimensional (1D) Y2O3:Tb3+ and Gd2O3:Tb3+ microrods have been successfully prepared through a large-scale and facile hydrothermal method followed by a subsequent calcination process in N-2/H-2 mixed atmosphere. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (IR), thermogravimetric analysis (TGA), energy-dispersive X-ray spectra (EDX). scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), photoluminescence (PL) and cathodoluminescence (CL) spectra as well as kinetic decays were used to characterize the samples. The as-formed products via the hydrothermal process could transform to cubic Y2O3:Tb3+ and Gd2O3:Tb3+ with the same morphology and slight shrinking in size after a postannealing process.

Enhanced luminescence of BPO4 by mixing with SiO2 and Al2O3

In this paper, BPO4-xSiO(2) (X: SiO2/BPO4 molar ratio, 0-70%) and BPO4-xAl(2)O(3) (X: Al2O3/BPO4 molar ratio, 0-20%) powder samples were prepared by the Pechini-type sol-gel (PSG) process using glycerol and poly(ethylene glycol) as additives. The structure and optical properties of the resulting samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), diffuse reflection spectra, photoluminescence (PL) excitation and emission spectra, kinetic decay, and X-ray photoelectron spectra (XPS), respectively. It was found that the Pechini-type sol-gel-derived BPO4-xSiO(2) annealed at 1000 degrees C and BPO4-xAl(2)O(3) annealed at 960 degrees C exhibited bright bluish-white emissions centered at 428 and 413 nm, respectively. The luminescence decay curve analysis indicates that each sample has two kinds of lifetimes (more than 0.4 ms and less than 10 ns) and two types of kinetic decay behaviors, which can be fitted into a double-exponential function and a single-exponential function, respectively.

Electrospinning Synthesis and Luminescence Properties of One-Dimensional Zn2SiO4:Mn2+ Microtibers and Microbelts

One-dimensional Mn2+-doped Zn2SiO4 rnicrobelts and microfibers were prepared by a simple and cost-effective electrospinning process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), energy-dispersive X-ray spectrum (EDS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL), and cathodoluminescence (CL) spectra as well as kinetic decays were used to characterize the samples. The XRD and DTA results show that the Zn2SiO4 phase begins to crystallize at 800 degrees C and crystallizes completely around 1000 degrees C. SEM results indicate that the as-prepared microbelts/fibers are smooth, whose diameters decrease with increasing the annealing temperature. The average diameter of the Zn2SiO4:Mn2+ microfibers annealed at 1000 degrees C is 0.32 mu m, and their lengths reach up to several millimeters. The average width and thickness of the Zn2SiO4:Mn2+ microbelts fired at 1000 degrees C are around 0.48 and 0.24 mu m, respectively.