Photoluminescence properties of Pb5(PO4)3Br:RE (RE = Dy3+, Eu3+ and Tb3+) phosphor synthesised using solid-state method.

This study describes the luminous properties of Pb5(PO4)3Br doped with RE3+ (RE = Dy3+, Eu3+ and Tb3+) synthesised using the solid-state method. The synthesised phosphor was characterised using Fourier-transform infrared, X-ray diffraction, scanning electron microscopy and photoluminescence measurements. Dy3+-doped Pb5(PO4)3Br phosphor exhibited blue and yellow emissions at 480 and 573 nm, respectively, on excitation at 388 nm. Eu3+-doped Pb5(PO4)3Br phosphor exhibited orange and red emissions at 591 and 614 nm, respectively, on excitation at λex = 396 nm. Pb5(PO4)3Br:Tb3+ phosphor exhibited the strongest green emission at 547 nm on excitation at λex = 380 nm. Additionally, the effect of the concentration of rare-earth ions on the emission intensity of Pb5(PO4)3Br:RE3+ (RE3+ = Dy3+, Eu3+ and Tb3+) phosphors was investigated.

Luminescence characterization of KBaPO4 :RE (RE = Sm3+ ,Eu3+ ,Dy3+ ) phosphors.

KBaPO4 luminescent powdered phosphors doped with rare earth elements (RE = Sm3+ ,Eu3+ ,Dy3+ ) were successfully synthesized using a wet chemical method to identify the most suitable phosphor for solid-state lighting based on the measurement of their emission spectra at excitation wavelengths. The X-ray diffraction pattern of the as-prepared KBaPO4 was well matched with its standard JCPDS file no. 330996, indicating the formation of the desired compound. Scanning electron microscopy images revealed irregular morphology, the material crystallized particles aggregated and were non-uniform with particle sizes ranging from 1 to 100 µm. Photoluminescence excitation and emission spectra clearly indicated that the phosphor containing the Sm3+ -activated KBaPO4 phosphors could be efficiently excited at 403 nm and exhibited an emission mainly including two wavelength peaks at 559 nm and 597 nm. The phosphor containing the Eu3+ -activated KBaPO4 phosphors could be efficiently excited at 396 nm and exhibited a bright red emission mainly including two wavelength peaks at 594 nm and 617 nm. The phosphor containing the Dy3+ -activated KBaPO4 phosphors could be efficiently excited at 349 nm and exhibited wavelength peaks at 474 nm and 570 nm.

Synthesis and photoluminescence properties of Eu3+ -activated Ba2 Mg(PO4 )2 phosphor.

In this paper, we have reported the photoluminescence (PL) properties of the Ba2 Mg(PO4 )2 :Eu3+ phosphor synthesized using a wet chemical method. The preliminary scanning electron microscopy (SEM) investigation of the sample revealed irregular surface morphology with particle sizes in the 10-50 µm range. The strongest PL excitation peak was observed at 396 nm. The emission spectra indicated that this phosphor can be effectively excited by the 396 nm wavelength. Upon 396 nm excitation, the emission spectrum showed characteristics peaks located at 592 nm and 615 nm. These intense orange-red emission peaks were obtained due to f→f transitions of Eu3+ ions. The emission peak at 592 nm is referred to as the magnetic dipole 5 D0 →7 F1 transition and the emission peak at 615 nm corresponded to the electric dipole 5 D0 →7 F2 transition of Eu3+ . The Commission Internationale de l'Eclairage (CIE) coordinates of the Ba2 Mg(PO4 )2 :Eu3+ phosphor were found to be (0.586, 0.412) for wavelength 592 nm and (0.680, 0.319) for wavelength 615 nm situated at the edge of the CIE diagram, indicating high colour purity of phosphors. Due to the high emission intensity and a good excitation profile, Eu3+ -doped Ba2 Mg(PO4 )2 phosphor may be a promising orange-red phosphor candidate for solid-state lighting applications.

Luminescence investigation of novel MgPbAl10O17:Tb³âº green-emitting phosphor for solid-state lighting.

In this work, we studied the luminescence properties of Tb(3+)-doped MgPbAl10O17 green phosphor. To understand the excitation mechanism and corresponding emission of the prepared phosphor, its structural, morphological and photoluminescence properties were investigated. In general, for green emission, Tb(3) is used as an activator and the obtained excitation and emission spectra indicated that this phosphor can be effectively excited by a wavelength of 380 nm, and exhibits bright green emission centered at 545 nm corresponding to the f → f transition of trivalent terbium ions. The chromaticity coordinates were (C(x) = 0.263, C(y) = 0.723). The impact of Tb(3+) concentration on the relative emission intensity was investigated, and the best doping concentration was found to be 2 mol%. This study suggests that Tb(3+)-doped MgPbAl10O17 phosphor is a strong candidate for a green component in phosphor-converted white light-emitting diodes.

Synthesis and characterization of blue long-lasting BaCa2Al8O15:Eu2+, Dy3+ phosphor.

We have synthesized and characterized a new BaCa2Al8O15:Eu(2+),Dy(3+) phosphor prepared by the combustion method. X-ray diffraction, thermoluminescence, scanning electron microscope, time decay and optical spectral analysis photoluminescence excitation, emission spectra were used to characterize the phosphors. Broadband ultraviolet excited luminescence of the BaCa2Al8O15:Eu(2+),Dy(3+) was observed in the blue region (λ(max) = 435 nm) due to transitions from the 4f(6)5d(1) to the 4f(7) configuration of the Eu(2+) ion. Scanning electron microscopy has been used for exploring the morphological properties of the prepared phosphors. The BaCa2Al8O15:Eu(2+) phosphor has a blue afterglow when Dy(3+) ions were co-doped. The thermoluminescence spectra show that the Dy(3+) ion induces a proper trap in the phosphor with a depth of 0.67 eV and results in a long afterglow phosphorescence.

Combustion synthesis of blue-emitting submicron CaAl4O7:Eu2+, Dy3+ persistence phosphor.

Long persistence phosphor CaAl4O7:Eu(2+), Dy(3+) were prepared by a combustion method. The phosphors were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), decay time measurement techniques and photoluminescence spectra (PL). The CaAl4O7:Eu(2+), Dy(3+) phosphor showed a broad blue emission, peaking at 445 nm when excited at 341 nm. Such a blue emission can be attributed to the intrinsic 4f → 5d transitions of Eu(2+) in the host lattices. The lifetime decay curve of the Dy(3+) co-doped CaAl4O7:Eu(2+) phosphor contains a fast decay component and another slow decay one. Surface morphology also has been studied by SEM. The calculated CIE colour chromaticity coordinates was (0.227, 043). We have also discussed a possible long-persistent mechanism of CaAl4O7:Eu(2+), Dy(3+) phosphor. All the results indicate that this phosphor has promising potential for practical applications in the field of long-lasting phosphors for the purposes of sign boards and defence.