Showing papers by "Xuhui Xu published in 2014"
TL;DR: In this paper, the bright blue emission at 420nm, originating from the charge transfer transition of the self-activated SnO 6 octahedron, was observed in Ca 3 SnSi 2 O 9 host matrix.
34 citations
TL;DR: A series of new luminescence emission-tunable phosphors KCaY(PO4)2: 0.03Ce3+, yTb3+ have been synthesized by high temperature solid-state reaction method as discussed by the authors.
33 citations
TL;DR: In this article, a n-UV convertible phosphor K3Gd(PO4)2:Tb3+, Eu3+ with tunable-emitting color has been synthesized by the solid state reaction.
32 citations
TL;DR: In this paper, the luminescent spectra showed that the emission intensity of Ag+ decreased while that of the Ag aggregates increased simultaneously, and the results indicated that the Ag ions intend to form the high-polymeric state such as ag aggregates and nanoparticles with increasing of europium ions.
29 citations
TL;DR: In this article, the trap properties of CaAl2O4:Eu2+, R3+ (R=Nd, Dy, Tm) materials were investigated and it was shown that the effective traps contributed to the LPL/OSL are complex.
26 citations
TL;DR: In this article, a series of CaYAl3O7: Ce3+, Tb3+ phosphors has been synthesized by combustion method for the first time, and XRD measurements demonstrated the phosphor hosts keep pure tetragonal crystalline structure at 850°C.
22 citations
TL;DR: In this paper, different ionic silver species and Ag nanoparticles (Ag NPs) were prepared by Ag + Na + ion exchange method in Tb 3+ -doped sodium-aluminosilicate glasses, and the interaction between Ag species and Tb3+ ions was studied.
Abstract: Different ionic silver species and Ag nanoparticles (Ag NPs) were prepared by Ag + –Na + ion exchange method in Tb 3 + -doped sodium–aluminosilicate glasses, and the interaction between Ag species and Tb 3 + ions was studied. Two excitation peaks centered at 280 nm and 375 nm which ascribed to Ag + and Ag aggregates (Ag 2 + , Ag 3 + …) respectively were observed in as-made glasses. Owing to energy transfer (ET) from Ag + /silver aggregates to Tb 3 + , significant enhancements of Tb 3 + emission were observed under certain excitation. After heat treatment, the results of absorption spectrum and TEM patterns revealed that silver nanoparticles (Ag NPs) with diameter of about 5 nm were formed in glasses, and it was found that the Ag NPs led to a significant enhancement in Tb 3 + luminescence under 375 nm excitation. A possible mechanism of energy transfer from Ag species to Tb 3 + ions was proposed.
22 citations
TL;DR: In this article, a red emitting phosphor of Eu{sup 3+} doped Ca{sub 2}Ge{sub 7}O{sub 16} was prepared through the solid state reaction.
21 citations
TL;DR: In this article, a large enhancement of photo-stimulated luminescence by co-doping Tm 3+ /Dy 3+ in α-Sr 2 SiO 4 was observed, upon the infrared (IR) stimulation at 980nm after pre-exposure with Ultraviolet (UV) light.
16 citations
TL;DR: In this article, the divalent europium ions promote the formation of silver aggregates in the process of ion exchange and significant enhancements of Eu3+ emission were observed for 285/350-nm excitation, respectively.
Abstract: Europium-doping sodium–aluminosilicate glasses are prepared by melt-quenching method, in which europium ions were spontaneously reduced from their trivalent to divalent state. The silver was introduced into glasses by Ag+–Na+ ion exchange and the interactions between europium ions and silver species were investigated. Owing to energy transfer (ET) from Ag+/silver aggregates to Eu3+, significant enhancements of Eu3+ emission were observed for 285/350-nm excitation, respectively. The divalent europium ions promote the formation of silver aggregates in the process of ion exchange.
16 citations
TL;DR: In this paper, a series of copper species, Tb3+, Mn2+ single-and co-doped oxyfluoride glasses were synthesized by a melt-quenching method.
Abstract: A series of copper species, Tb3+, Mn2+ single- and co-doped oxyfluoride glasses were synthesized by a melt-quenching method. The photoluminescence properties of the glasses containing copper species were demonstrated. Results indicate that the blue-green emission band peaking at 440 nm was observed, which was ascribed to the photoluminescence of Cu+ ions rather than the emissions of Cu2+ cations or Cu nano-particles (Cu NPs) induced by local field effect (LFE) enhancement through surface plasmon resonance (SPR). The interaction mechanisms between Cu+ and Tb3+/Mn2+ have been systematically investigated, and significant enhancement of Cu+ emission and the energy-transfer (ET) efficiencies of Cu+→Tb3+ and Cu+→Mn2+ were observed in glasses doped with SnO reducing agent. Furthermore, a wide-range-tunable emission and ideal white-light fluorescence were realized in Cu+/Tb3+/Mn2+-coactivated glasses by utilization of Cu+ cations as dual ET contributors from deep-UV-source to multiactivators. Our research further extends the understanding of the interactions between Cu+ and Tb3+/Mn2+ in amorphous materials.
TL;DR: In this article, a series of trichromatic/white-emitting 15CaO-55B 2 O 3 -30SiO 2 glasses co-doped with Ce 3+ /Tb 3+ + /Mn 2+ were synthesized in air by a melt-quenching method.
Abstract: A series of trichromatic/white-emitting 15CaO–55B 2 O 3 –30SiO 2 glasses co-doped with Ce 3 + /Tb 3 + /Mn 2 + were synthesized in air by a melt-quenching method. Ce 3 + ions played a role as sensitizers in improving the photoluminescence performance of multi-activators. Dual energy transfer (ET) processes of Ce 3 + → Tb 3 + and Ce 3 + → Mn 2 + were observed in Ce 3 + –Mn 2 + –Tb 3 + co-activated glasses. The hues of the fabricated glasses covered the regions from blue, green, to orange–red, and a wide-range-tunable warm white light emission was realized by tuning the ET proportion from excitation source to the co-activated Mn 2 + and Tb 3 + ions through utilizing Ce 3 + ions as the multi-sensitizers. It indicates that these glasses are expected to be potential phosphor candidates for deep UV-pumped white-LED.
TL;DR: A greenish-blue long-persistent luminescence (LPL) material of Ba4(Si3O8)2:Eu2+,Er3+ was synthesized by traditional solid state reaction method as mentioned in this paper.
TL;DR: In this article, Li, Na+, and K+ ions were introduced into CaYAl3O7: M (M=Eu3O 7: Eu3+ phosphor) as charge compensators.
Abstract: Monovalent ions Li+, Na+, and K+, as charge compensators, are introduced into CaYAl3O7: M (M=Eu3+, Ce3+) in this letter. Their crystal phases and photoluminescence properties of different alkali metal ions doped in CaYAl3O7 are investigated. In addition, the influence of charge compensation ion Li+ which has a more obvious role in improving luminescence intensity on CaYAl3O7: Eu3+ phosphor is intentionally discussed in detail and a possible mechanism of charge compensation is given. The enhancement of red emission centered at 618 nm belonging to Eu3+ is achieved by adding alkali metal ion Li+ under 393-nm excitation.
TL;DR: In this paper, a series of K3Gd1−x−y(PO4)2:xCe3+, yTb3+ phosphors are synthesized by the solid-sate reaction method.
Abstract: A series of K3Gd1−x−y(PO4)2:xCe3+, yTb3+ phosphors are synthesized by the solid-sate reaction method. X-ray diffraction and photoluminescence spectra are utilized to characterize the structures and luminescence properties of the as-synthesized phosphors. Co-doping of Ce3+ enhances the emission intensity of Tb3+ greatly through an efficient energy transfer process from Ce3+ to Tb3+. The energy transfer is confirmed by photoluminescence spectra and decay time curves analysis. The efficiency and mechanism of energy transfer are investigated carefully. Moreover, due to the non-concentration quenching property of K3Tb(PO4)2, the photoluminescence spectra of K3Tb1−x(PO4)2:xCe3+ are studied and the results show that when x = 0.11 the strongest Tb3+ green emission can be realized.
TL;DR: In this article, the relationship between Bi near-infrared (NIR) luminescence and the glass structure was investigated, and the intensity of the NIR emission increased firstly and then declined with the increasing CaO content, which cannot explain the theory of optical basicity.
Abstract: Bismuth doped calcium germanate glasses were prepared, and the relationship between Bi near-infrared (NIR) luminescence and the glass structure was investigated. The NIR emission with 808 nm excitation covered the whole optical telecommunication window. The intensity of the NIR emission increased firstly and then declined with the increasing CaO content, which cannot be explained by the theory of optical basicity. The X-ray photoelectron spectroscopy (XPS) and the visible luminescence spectra showed that the trivalent Bi 3+ could reduce to lower state of Bi in these glasses. The Fourier transform infrared (FT-IR) absorption spectra and Raman spectra indicated that the major structure units were [GeO 4 ] tetrahedral, and the 4-membered [GeO 4 ] rings converted into 3-membered [GeO 4 ] rings with the increasing optical basicity. The nature of NIR emission and the reason of the abnormal phenomenon were discussed.
TL;DR: In this paper, a series of Ca4.99(PO4)3F:1%Eu3+, 1%X (X = Li+, Au3+, and Bi3+) nanoparticles are prepared using hydro-thermal method, with an average size of 33-62 nm.
Abstract: A series of Ca4.99(PO4)3F:1%Eu3+, 1%X (X = Li+, Au3+, and Bi3+) nanoparticles
are prepared using hydrothermal method, with an average size of 33-62 nm. We study
the improved photoluminescence properties of Ca4.99(PO4)3F:1%Eu3+ by co-doping with
Li+, Au3+, and Bi3+ ions, respectively, and the enhancement of the emission
intensities of Eu3+ is observed in these samples. The effects of Li+ acting as a
charge compensator, Au3+ as a plasma surface sensitizer, and Bi3+ as an energy
conversion agent are discussed. The results show Ca4.99(PO4)3F:1%Eu3+, 1%X
nanoparticles are a promising candidate as a red component for near-ultraviolet
light-emitting diodes.
TL;DR: In this article, the structural and luminescent properties of Eu3+activated red-emitting Ba2Gd2Si4O13 phosphors are investigated by X-ray diffraction (XRD), photoluminescence (PL) spectra and scanning electron microscopy (SEM).
Abstract: Eu3+-activated red-emitting Ba2Gd2Si4O13 phosphors are prepared via microwave (MW) synthesis and solid-state (SS) method. The structural and luminescent properties of phosphors are investigated by X-ray diffraction (XRD), photoluminescence (PL) spectra and scanning electron microscopy (SEM). Upon 393 nm excitation, compared with the sample sintered by SS method, luminescence enhancement is observed in the sample synthesized by MW method. The mechanism of MW synthesis process is discussed in detail. Results indicate that the PL enhancement is probably related to the concave-convex phosphor surfaces and uniform grains, which may reinforce scattering of excitation light. Our research may further promote the understanding of MW synthesis and extend the application of Eu3+-activated Ba2Gd2Si4O13 in white light-emitting diodes.
TL;DR: In this paper, the photoluminescence of Eu3+-doped glass with Bi3+ as a sensitizer was investigated and the specific glass system with the strong enhancement of the red emission was obtained by adding a small number of bi3+ ions instead of increasing the Eu 3+ concentration.
Abstract: We report the photoluminescence (PL) of Eu3+-doped glass with Bi3+ as a sensitizer. The specific glass system with the strong enhancement of the red emission of Eu3+ is obtained by adding a small number of Bi3+ ions instead of increasing the Eu3+ concentration. The emission band of Bi3+ overlaps with the excitation band of Eu3+ and the lifetime decay curves, resulting in a very efficient energy transfer from Bi3+ to Eu3+. The probability of energy transfer is strongly dependent on Bi3+ concentration. In addition, the intensity of 4f–4f transition is much stronger than that of a charge-transfer (CT) band in the excitation spectrum, which indicates that the Na2O—CaO—GeO2-SiO2 glass is a suitable red-emitting phosphor with high stability as a candidate for light-emitting diodes (LEDs).