Combustion Synthesis and Photoluminescence Properties of Novel Bi2Al4O9:Eu3+ Phosphor for n-UV w-LEDs.

The combustion procedure was used to synthesize Bi2Al4O9:Eu3+ phosphors. The XRD and photoluminescence properties are investigations. The XRD patterns consist of an orthorhombic crystal structure. At 395 nm, the maximum excitation intensity was obtained. Following 395 nm excitation, two different emission peaks at 593 and 615 nm were observed. Concentration quenching occurred at 0.5 mol % Eu3+ ions. The CIE coordinates for the Bi2Al4O9 phosphor with Eu3+ ion doped are 615 nm (x = 0.680, y = 0.319) falling in the red region. According to the photoluminescence results, Bi2Al4O9:Eu3+ phosphors might be useful in the fields of near UV-excited w-LEDs.

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.

Dy3+ -, Sm3+ -, Ce3+ - and Tb3+ -activated optical properties of microcrystalline BaMgP2 O7 phosphors.

Photoluminescence (PL) and thermoluminescence (TL) properties of rare earth (RE) ion (RE = Dy3+ , Sm3+ , Ce3+ , Tb3+ ) activated microcrystalline BaMgP2 O7 phosphors are presented in this work. Non-doped and doped samples of BaMgP2 O7 were prepared using a solid state diffusion method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), PL and TL. The XRD measurement confirmed the phase purity of the BaMgP2 O7 host matrix. The average particle size was found through SEM measurement to be around 2 µm. All activators using the PL technique displayed characteristic excitation and emission spectra that corresponded to their typical f â†’ f and f â†’ d transitions respectively. Thermoluminescence measurements showed that BaMgP2 O7 :RE (RE = Dy3+ , Sm3+ , Tb3+ , Ce3+ ) and co-doped BaMgP2 O7 :Ce3+ ,Tb3+ phosphors have also TL behaviour.

A novel red-emitting phosphor, KAl1-xPO4Cl:Eux(3+) (0.1 ≤ x ≤ 1.0).

A series of phosphors KAl1-xPO4Cl:Eux(3+) (0.1 ≤ x ≤ 1.0) was synthesized using a facile combustion method using urea as a fuel and their structural, morphological and photoluminescence properties were investigated. It was found that the particle size was in the range of 1-2 µm with an irregular shape. The f-f transitions of Eu(3+) in the host lattice were assigned and discussed. The excitation and emission spectra indicated that this phosphor can be efficiently excited by ultraviolet (395 nm), and exhibit reddish orange emission corresponding to the (5)D0 →(7)FJ (J = 0, 1, 2) transitions of Eu(3+). The impact of the Eu(3+) concentration on the relative emission intensity was investigated, and the best doping concentration is 0.5. The present study suggests that the KAl0.5PO4Cl:Eu0.5(3+) phosphor is a strong candidate as a red component for phosphor- converted white light-emitting diodes (LEDs).

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.

Enhanced luminescence and white light emission from Eu(3+) -co-doped K3 Ca2 (SO4 )3 Cl:Dy(3+) phosphor with near visible ultraviolet excitation for white LEDs.

The luminescent properties of europium (Eu)- and dysprosium (Dy)-co-doped K3 Ca2 (SO4 )3 Cl halosulfate phosphors were analyzed. This paper reports the photoluminescence (PL) properties of K3 Ca2 (SO4 )3 Cl microphosphor doped with Eu and Dy and synthesized using a cost-effective wet chemical method. The phosphors were characterized by X-ray diffraction and scanning electron microscopy. The CIE coordinates were calculated to display the color of the phosphor. PL emission of the prepared samples show peaks at 484 nm (blue), 575 nm (yellow), 594 nm (orange) and 617 nm (red). The emission color of the Eu,Dy-co-doped K3 Ca2 (SO4 )3 Cl halophosphor depends on the doping concentration and excitation wavelength. The addition of Eu in K3 Ca2 (SO4 )3 Cl:Dy greatly enhances the intensity of the blue and yellow peaks, which corresponds to the (4) F9/2 → (6) H15/2 and (4) F9/2 → (6) H13/2 transitions of Dy(3+) ions (under 351 nm excitation). The Eu(3+) /Dy(3+) co-doping also produces white light emission for 1 mol% of Eu(3+) , 1 mol% of Dy(3+) in the K3 Ca2 (SO4 )3 Cl lattice under 396 nm excitation, for which the calculated chromaticity coordinates are (0.35, 0.31). Thus, K3 Ca2 (SO4 )3 Cl co-doped with Eu/Dy is a suitable candidate for NUV based white light-emitting phosphors technology.

Photoluminescence in K3 Ca2 (SO4 )3 Cl-doped Eu(3+) phosphor.

In this article we report Eu(3+) luminescence in novel K3 Ca2 (SO4 )3 Cl phosphors prepared by wet chemical methods. The Eu(3+) emission was observed at 594 nm and 615 nm, keeping the excitation wavelength constant at 396 nm nearer to light-emitting diode excitation, Furthermore, phosphors were characterized by X-ray diffraction for the confirmation of crystallinity. The variation of the photoluminescence intensity with impurity concentration has also been discussed. Thus, prominent emission in the red region makes prepared phosphors more applicable for white light-emitting diodes.

Photoluminescence of Alq3 - and Tb-activated aluminium-tris(8-hydroxyquinoline) complex for blue chip-excited OLEDs.

The tris(8-hydroxyquinoline)-aluminium complex is the most important and widely studied as electron transporting and green light emitting material. Alq(3) and Tb(x) Al((1-x)) q(3) have been synthesized (where x = 0.1, 0.3, 0.5, 0.7 and 0.9) and blended films of Alq(3) and Tb(x) Al((1-x)) q(3) with PMMA and PS at different percentage weight (wt%) concentrations (e.g., 0.1, 1, 5, 10, 25 and 50 wt%) have been prepared. The synthesized materials and their blended thin films have been characterized by a photoluminescence (PL) technique; the synthesis and PL characterization are reported in this paper. The synthesized metal complex shows bright emission of green light with blue light excitation (440 nm) and the prepared Tb(x) Al((1-x)) q(3) phosphor may be applicable in blue chip-excited OLEDs for the newly developed wallpaper lighting technology.