Bin Deng

Luminescence and thermal-quenching properties of silicate-based red-emitting K4CaSi3O9:Eu3+ phosphor

A series of novel silicate-based red-emitting K4Ca1−xSi3O9:xEu3+ (xu2009=u20090.01–0.30) phosphors were successfully synthesized via a high-temperature solid-state reaction method for the first time. The compounds were crystallized in the cubic structure with the space group Pa

Synthesis and optical properties of orange–red emitting Sm 3+ -activated Ca 9 LiGd 2/3 (PO 4 ) 7 phosphors

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Preparation and study on the spectral properties of garnet-type Li 3 Gd 3 Te 2 O 12 :Dy 3+ single-phase full-color phosphor

3¯. The photoluminescence spectrum of K4CaSi3O9:Eu3+ phosphor shows four peaks assigned to the 5D0–7FJ (Ju2009=u20090, 1, 2, 3 and 4) transitions of Eu3+ upon 396xa0nm excitation. Judd–Ofelt intensity parameters and CIE were calculated from the photoluminescence data. The quenching temperature for K4CaSi3O9:0.30Eu3+ was estimated to be above 500xa0K. The superior thermal stability can be attributed to the rigid structure of the host. The good color saturation and high thermal stability indicate that K4CaSi3O9:Eu3+ phosphor is a potential candidate for light-emitting diodes.

A multicolor phosphor of self- and Eu3+-activated La3Ga4TiO14

A novel blue-emitting phosphor, Li3Gd3Te2O12:Tm3+ for white light-emitting diodes (W-LEDs) was prepared by solid-state synthesis and its structure and luminescence properties were investigated. This phosphor shows a satisfactory blue performance (peak at 458 nm) due to the 1D2 → 3F4 transition of Tm3+ excited by 361 nm light. Investigation of Tm3+ content dependent emission spectra indicates that x = 0.03 is the optimum doping content of Tm3+ ions in the Li3Gd3Te2O12 host. The critical distance and the concentration quenching mechanism were also investigated. In particular, the color purity of as-prepared sample is close to that of the commercial blue phosphor BaMgAl10O17:Eu2+ (BAM:Eu2+). The present work suggests that the Li3Gd3Te2O12:Tm3+ phosphor is a potential blue-emitting candidate for the application in the near-UV WLEDs.

New Eu 3+ -activated bismuthate tellurate LiSrBiTeO 6 red-emitting phosphor for InGaN-based w-LEDs

The phosphors of Sm3+-activated Ca9LiGd2/3(PO4)7 are synthesized through a solid state reaction. The X-ray powder diffraction analysis, photoluminescence excitation and emission spectra, thermal quenching were applied to investigate the phase structure, luminescence, and thermal stability properties. The emission spectra of the Ca9LiGd2/3(PO4)7:Sm3+ phosphors consisted of some sharp emission peaks of Sm3+ ions centered at 562, 601, 646, 708xa0nm. The strongest one is located at 604xa0nm due to 4G5/2–6H7/2 transition of Sm3+, generating bright orange–red light. The optimum doping concentration of Sm3+ ions is measured to be 15xa0mol%. The critical transfer distance of Sm3+ is calculated as 20xa0Å. The thermal-quenching temperature is above 500xa0K. The CIE chromaticity coordinates of the Ca9LiGd2/3(PO4)7:0.15Sm3+ phosphor were located in the orange–reddish region. It shows strong absorption in 350–420xa0nm region, which has great potential red phosphors for white light-emitting diodes.

Eu3+-doped highly thermal-stable barium yttrium aluminate as a red-emitting phosphor for UV based white LED

A new phosphor of the type Gd8(1-x) Eu8u2009x V2 O17 (x=0-1.0) was synthesized through the solid-state reaction ceramics method. A pure phase formation was verified by using X-ray powder diffraction measurements. The luminescence of Gd8 V2 O17 :Eu3+ was investigated through optical and laser excitation spectroscopy. The luminescence curves were investigated in the temperature region 10 to 300u2005K. Gd8 V2 O17 shows a self-activated luminescence under excitation with UV- and near-UV light. The spectra, the decay lifetimes, and the thermal stability of Gd8(1-x) Eu8u2009x V2 O17 (x=0.005-1.0) strongly depend on both the Eu3+ concentration and the temperature. The tunable luminescence is realized by controlling the Eu3+ -doping level to adjust the host energy-transfer efficiency from the VO43- groups to the Eu3+ activators. At low Eu3+ concentrations (<30u2005molu2009%), the intensity and lifetime show an unusual change with an increase of the temperature from 10-300u2005K, that is, the luminescence experiences a straightforward enhancement. The energy transfer from the VO43- group to the Eu3+ ions could be accelerated with an increase of the temperature resulting in an unusual enhancement of the Eu3+ luminescence and lifetime. However, the emission of the Eu3+ ions decreased for highly Eu-doped samples (>30u2005molu2009%) with an increase of the temperature. The luminescence mechanism was discussed on the basis of the charge-transfer band of the Eu3+ ions, the doping concentration, and the proposed microstructures in the lattices.