Photoluminescence Properties Of Phosphors Research Articles

Synthesis and photoluminescence properties of CaMgAl10O17:Sm3+ phosphor for n-UV solid-state lighting

The combustion method was used to synthesize CaMgAl10O17:Sm3+ phosphor. The scanning electron microscopy and photoluminescence properties of phosphors were thoroughly investigated. The emission spectrum has three distinct peaks at 563, 604 and 642 nm under 405 nm excitation, which is corresponding to the transitions 4G5/2→6H5/2, 4G5/2→6H7/2 and 4G5/2→6H9/2 of Sm3+ ions. The optimum concentration of CaMgAl10O17:Sm3+ phosphor was discovered to be 1 mole %, above which concentration quenching was observed. The CIE coordinates for the CaMgAl10O17 phosphor with Sm3+ ion doped are 604 nm (x=0.644, y=0.355) falling in the red region. According to the current findings, CaMgAl10O17:Sm3+ phosphors might be useful in the fields of near UV-excited solid-state lighting.

Synthesis and luminescence properties of (Dy3+, Eu3+) ions co-doped double-perovskite Ba2LaNbO6 phosphors

Dy[Formula: see text] and Eu[Formula: see text] ions co-doped double-perovskite Ba2LaNbO6 phosphor was prepared by a high-temperature solid-state reaction method. The effects of ions co-doping concentration onto the crystal structures, surface morphologies and photoluminescence properties of phosphors were elucidated by using X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), and fluorescence spectrophotometer, respectively. The XRD patterns reveal that the crystallization of Dy[Formula: see text] and Eu[Formula: see text] ions co-doped Ba2LaNbO6 was monoclinic phase with space group of C2/m. For the Dy[Formula: see text] ion-doped Ba2LaNbO6 phosphors under an excitation wavelength of 293 nm, the main emission wavelengths are between 460 and 520 nm and 560 and 620 nm, which are due to the 4F[Formula: see text]H[Formula: see text] magnetic dipole transition and the 4F[Formula: see text]H[Formula: see text] super sensitive transition of Dy[Formula: see text] ion, respectively. The concentration quenching effect occurs as the Dy[Formula: see text] ion concentration is 4 mol%. The CIE chromaticity coordinates shift from the light blue region to the green region as the Dy[Formula: see text] ion doping concentration increases. When the Dy[Formula: see text] and Eu[Formula: see text] ions co-doped Ba2LaNbO6 phosphors, the CIE chromaticity coordinates of Ba2(La[Formula: see text] Dy[Formula: see text]Eu[Formula: see text]Nbo6 phosphors are moved from the green light region to the near white-light region due to the mixing of the strong magnetic dipole transition of 5D[Formula: see text]F1 at 594 nm, and electric dipole transition of 5D[Formula: see text]F2 at 617 nm for the characteristic [Formula: see text]–[Formula: see text] transition of Eu[Formula: see text] ion.

A new strategy to the NaY(MoO4)2:Eu3+ phosphors modified by tetraethyl orthosilicate for LEDs: Photoludminescence properties and morphology

NaY(MoO4)2:Eu3+ microcrystals with different morphologies have been successfully synthesized via a hydrothermal method by varying the molar ratios of tetraethyl orthosilicate (TEOS). The structure and photoluminescence properties of phosphors are investigated by the X-ray powder diffraction (XRD), transmission electron microscope (TEM), the ultraviolet-visible diffuse reflectance spectra (UV–vis DRS), photoluminescence excitation (PLE) and emission (PL) spectra as well as the decay curves. There are two intense PLE peaks at 395 and 465 nm in the PLE spectra, which well matched with the near ultraviolet (NUV) and blue GaN-based light-emitting diodes (LEDs). In the PL spectra, the strongest PL peak is caused by 5D0 → 7F2 electric dipole transition. In addition, the amount of TEOS has an important impact on the morphologies and PL intensity of samples. With the increase of the amount of TEOS, the morphologies of the samples vary from double shuttle-like architectures, truncated rhombic polyhedrons, to quasi-cubes. It is found that the International Commission on Illumination (CIE) chromaticity coordinates of phosphors are located in red region, and the color purity is 99.70 % for S2 sample. Besides, the correlated color temperature (CCT) values of S1−3 samples are in the range of “warm appearance”. Therefore, the above obtained results suggest that the samples possess potential application value in the field of optical display systems, photoelectric devices and LEDs.

Low temperature synthesis and photoluminescence properties of Mn4+-doped La2MgTiO6 deep-red phosphor with a LiCl flux

Abstract A series of Mn4+ doped La2MgTiO6 red-emitting materials with double-perovskite structure and high efficient red emission have been successfully prepared by molten salt assisted method which LiCl acting as molten salt at a relatively low temperature. The effects of the reaction temperature and the usage amounts of LiCl on the structure and photoluminescence properties of phosphors were studied. Experimental results indicate that the synthesis temperature of the Mn4+-doped La2MgTiO6 by molten salt method is only 800 °C while the traditional solid phase method requires 1350 °C. The morphology and particle size of phosphors can be well controlled by adjusting the reaction temperature and the amount of molten salt. The thermal stability and quenching mechanism of phosphors were studied by temperature dependent emission spectra, which demonstrated that LiCl is benefit to improve the thermal stability of the Mn4+activated La2MgTiO6 phosphors.

Effect of reduction co-sintering on the photoluminescence properties of phosphor in glass in boro-bismuthate glass

Phosphor in glass (PiG) employing Ce:Y3Al5O12 (YAG)-doped boro-bismuthate glass via low-temperature co-sintering technology was successfully prepared, using Bi2O3-B2O3-ZnO glass as the base material. The photoluminescence (PL) of PiG co-sintered at times ranging from 20 min to 60 min at 700°C was investigated. As a result, the relative PL intensity of PiG under a reducing atmosphere of CO showed significant enhancement of about 7–14 times that under air atmosphere sintering for 20–50 min. The PL intensity decreased gradually with the co-sintering time, which may be due to the corrosion of the YAG lattice structure.

Effect of K+ ions on the photoluminescence properties of Ca4.75(PO4)3Cl: 0.05Eu2+, 0.2Mn2+ phosphors

K+ ions were incorporated into Ca4.75(PO4)3Cl: 0.05Eu2+, 0.2Mn2+ Phosphors, which has a significant effect on the photoluminescence properties of phosphors. With increasing the K+ concentration (x value) in Ca4.75−xKx(PO4)3Cl: 0.05Eu2+, 0.2Mn2+ (x=0-0.15), the emission intensity of Eu2+ increases and reaches its maximum value at the x=0.1, and then decreases for the higher K+ concentrations, which can be explained by charge compensations and crystal lattice strain relaxing. The results show a potential for increasing the emission intensity of Ca4.75(PO4)3Cl: 0.05Eu2+, 0.2Mn2+ phosphors by properly doping K+ ions.

Luminescent Properties of Eu<sup>3+</sup>-Doped BaGd<sub>2</sub>ZnO<sub>5</sub> Phosphors for White LED

BaGd2ZnO5:Eu3+ phosphors were synthesized at sintering temperatures of 800, 900, 1000, 1100 and 1200 °C by high-energy ball milling method. The crystallinity, surface morphology and photoluminescence properties of phosphors were investigated by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and luminescence spectrophotometry, respectively. The XRD results indicate that the crystallinity of the powder was improved and the powder shows a orthorhombic structure as the sintering temperature increased. The emission spectra of BaGd2ZnO5phosphors excited at 280 nm exhibit a series of shaped peaks assigned to the5D0→7FJ(J=0, 1, 2, 3) transitions, and luminescence intensity was increased with increasing sintering temperature. The FE-SEM images indicate that the size and shape of particles are regular.

Photoluminescence properties of Zn0.9Mg0.1S phosphors doped by europium and manganese ions

The Zn0.9Mg0.1S:mEu2+, nMn2+ phosphors were synthesized by solid-state reactions via double-crucible method. The obtained phosphors exhibit two broad bands, the blue 460nm emission band is originated from the 5d–4f transition of Eu2+ ions, while the yellow 570nm emission band is originated from the 4T1–6A1 transition of Mn2+ ions in Zn0.9Mg0.1S host, and show white color under an ultraviolet (UV) source by adjusting the ratio of Eu2+ and Mn2+ appropriately. The energy transfer from Eu2+ to Mn2+ is confirmed by the photoluminescence properties of phosphors and the decay life time measurements. The optimal composition of Zn0.9Mg0.1S:0.02Eu2+, 0.004Mn2+ generates warm white light with chromaticity coordinates (0.350, 0.385), indicating that Zn0.9Mg0.1S:mEu2+, nMn2+ phosphors would be a good single-phased white-emitting phosphor for full color display.

Synthesis and photoluminescence properties of LiEu(W,Mo)2O8:Bi3+ red-emitting phosphor for white-LEDs

LiEu1−x(W2−yMoy)O8:xBi3+ series red-emitting phosphors were synthesized by solid state reaction. The structure, morphology, and photoluminescent properties of phosphors were studied by X-ray powder diffraction, scanning electron microscopy, and photoluminescence spectrum, respectively. X-ray powder diffraction analysis showed that the as-obtained phosphors belong to the scheelite structure. The average particle size of the investigated phosphor was about 8 μm. The excitation spectrum exhibits a charge-transfer broad band along with some sharp peaks from the typical 4f–4f transitions of Eu3+. Under excitation of UV, near-UV, or blue light, these phosphors showed strong red emission at 615 nm due to 5D0–7F2 transition of Eu3+. The incorporation of Mo6+ into LiEuW2O8:Bi3+ could induce red-shift of the charge-transfer broad band and a remarkable increase of photoluminescence. The highest red-emission intensity was observed with LiEu0.80Mo2O8:0.20Bi3+. Compared with the commercial red-emitting phosphor, Y2O2S:Eu3+, the emission intensity of LiEu0.80Mo2O8:0.20Bi3+ phosphor is much stronger than that of Y2O2S:Eu3+ and its chromaticity coordinates are closer to the standard values than that of the commercial phosphor. The optical properties of LiEu0.80Mo2O8:0.20Bi3+ phosphor make it attractive for the application in white-light-emitting diodes (LEDs), in particular for near-UV InGaN-based white-LEDs.

Effects of Eu[sup 2+] Co-Doping on VUV Photoluminescence Properties of BaMgAl[sub 10]O[sub 17]:Mn[sup 2+] Phosphors for Plasma Display Panels

The effects of co-doping were examined on vacuum ultraviolet (VUV) photoluminescence properties of phosphors. The phosphors were synthesized with various Eu concentrations ranging from 0 to 2 atom %. When Eu ions were added, the blue luminescence appeared with the decrease in the green luminescence. With increasing Eu concentration, the decay time gradually decreased from (0 atom %) to (2 atom %). The energy-transfer efficiencies were analyzed with the average-decay time acquired by a double-exponential fitting, and the 2 atom % Eu sample showed the energy-transfer efficiency of 19%.