A new Ca15(PO4)2(SiO4)6:Eu 2+ phosphor with green emission for use in n-UV based WLEDs (original) (raw)
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Journal of Rare Earths, 2010
A blue phosphor Ca 2 PO 4 Cl:Eu 2+ (CAP:Eu 2+ ) was synthesized by solid state reaction. The Ca 2 PO 4 Cl:Eu 2+ exhibited high quantum efficiency and excellent thermal stability. The luminescent intensity of Ca 2 PO 4 Cl:Eu 2+ was found to be 128% under excitation at 380 nm, 149% under 400 nm, and 247% under 420 nm as high as that of BaMgAl 10 O 17 :Eu 2+ . The optimal doping concentration was observed to 11 mol.% of CAP:Eu 2+ . The energy transfer between Eu 2+ ions in CAP were occurred via electric multipolar interaction, and the critical transfer distance was estimated to be 1.26 nm. A mixture of blue-emitting Ca 2 PO 4 Cl:Eu 2+ , green-emitting (Ba,Sr) 2 SiO 4 :Eu 2+ and red-emitting CaAlSiN 3 :Eu 2+ phosphors were selected in conjunction with 400 nm chip to fabricate white LED devices. The average color-rendering index R a and correlated color temperature (T c ) of the white LEDs were found to be 93.4 and 4590 K, respectively. The results indicated that it was a promising candidate as a blue-emitting phosphor for the near-UV white light-emitting diodes.
Journal of Materials Chemistry, 2010
A blue phosphor Ca 2 PO 4 Cl : Eu 2+ was synthesized by solid state reaction and evaluated as a candidate for white LEDs. The luminescent intensity of Ca 2 PO 4 Cl : Eu 2+ was found to be 128% under excitation at 380 nm, 149% under 400 nm, and 247% under 420 nm, as high as that of BaMgAl 10 O 17 : Eu 2+ . Furthermore, Ca 2 PO 4 Cl : Eu 2+ reveals high quantum efficiency and excellent thermal stability. By utilizing a mixture of blue-emitting Ca 2 PO 4 Cl : Eu 2+ , green-emitting (Ba,Sr) 2 SiO 4 : Eu 2+ and redemitting CaAlSiN 3 : Eu 2+ as light converters, an intense white GaN-based n-UV-LED (400 nm) was fabricated to exhibit an excellent color-rendering index R a of 93.4 at a correlated color temperature of 4590 K. Based on the results, we are currently evaluating the potential application of Ca 2 PO 4 Cl : Eu 2+ as a blue-emitting near-UV convertible phosphor.
The luminescence efficiency of green phosphorCa7(PO4)2(SiO4)2:Eu2+ for white light-emitting diode
Indonesian Journal of Electrical Engineering and Computer Science, 2022
This study examines the green-emission phosphor composition of Eu2+ doped Ca7(PO4)2(SiO4)2 to serve the goal of efficiency enhancement for the white light emitting diode (LED). The process of preparation and photo luminescent investigation of proposed phosphor composition was monitored under near UV excitation wavelength of the LED die. The sample phase was determined using X-ray diffractometer (XRD). To exploreCa7(PO4)2(SiO4)2:Eu2+ capabilities, the diffuse reflectance and photo lumine- scence spectral figures were employed. The ultraviolet absorption of Ca7(PO4)2(SiO4)2:Eu2+ ranged from 240 to 440 nm, with a wide band of green emission peaking at 522 nm. Besides the concentration quenching mechanism, we also focus on essential characteristics for white-light- emitting diode (WLED) production like temperature-dependent lumen output and chromaticity coordinates.
Optical Materials Express, 2014
A novel green emitting phosphor of Eu 2+ doped Ca 7 (PO 4) 2 (SiO 4) 2 was synthesized and its photoluminescence properties were investigated for application in UV LEDs. XRD was used to identify sample phase. Diffuse reflection spectra and photoluminescence spectra were used to investigate its photoluminescence properties. Ca 7 (PO 4) 2 (SiO 4) 2 :Eu 2+ showed an absorption ranging from 240 to 440 nm in ultraviolet range and a broad green emission band peaked at 522 nm. The concentration quenching mechanism and the key parameters for the fabrication of WLEDs, such as the temperature dependent photoluminescence and CIE value had also been studied.
Eu^2+-activated silicon-oxynitride Ca_3Si_2O_4N_2: a green-emitting phosphor for white LEDs
Optics Express, 2011
The green-emitting phosphor Ca 3 Si 2 O 4 N 2 :Eu 2+ was synthesized using a solid-state reaction. The luminescence properties, diffuse reflection spectrum, and thermal quenching were firstly studied, and a white lightemitting diode (wLED) was fabricated using the Eu 2+ -activated Ca 3 Si 2 O 4 N 2 phosphor. Eu 2+ -doped Ca 3 Si 2 O 4 N 2 exhibited a broad green emission band centered between 510 and 550 nm depending on the concentration of Eu 2+ . The optimal doping concentration of Eu 2+ in Ca 3 Si 2 O 4 N 2 was 1 mol%. The energy transfer between Eu 2+ ions proceeds by an electric multipolar interaction mechanism, with a critical transfer distance of approximately 30.08 Å. A wLED with an color-rendering index R a of 88.25 at a correlated color temperature of 6029 K was obtained by combining a GaN-based n-UV LED (380 nm) with the blue-emitting BaMgAl 10 O 17 :Eu 2+ , green-emitting Ca 3 Si 2 O 4 N 2 :Eu 2+ , and red-emitting CaAlSiN 3 :Eu 2+ phosphors. The results present Ca 3 Si 2 O 4 N 2 :Eu 2+ as an attractive candidate for use as a conversion phosphor for wLED applications.
Journal of Luminescence, 2020
Eu 3þ-activated Ca 3 Mo 0.2 W 0.8 O 6 phosphors, which presented bright red emissions mainly from the 5 D 0 → 7 F 2 transition of Eu 3þ ions upon the near-ultraviolet and blue light excitation, were successfully prepared by a traditional high-temperature technology. The crystal structure, phase constitution, morphology, electronic structure, photoluminescent behaviors, decay time, internal quantum efficiency and thermal stability of the resultant phosphors were investigated in detail. Under the excitation of 365, 393 and 465 nm, the optimal doping concentration was 9 mol% and the electrical multipolar interaction contributed to the non-radiative energy transfer between Eu 3þ ions in Ca 3 Mo 0.2 W 0.8 O 6 host lattices. Additionally, through using the prepared compounds, commercial blue/green-emitting phosphors and light-emitting diodes (LEDs), the fabricated white-LEDs emitted warm white light with excellent performance, such as good CIE coordinates, high color rending index and low correlated color temperature, when driven by 30 mA of injection current. Ultimately, according to the response of the decay time to the temperature, the thermometric performances of the resultant phosphors in the temperature range of 298-573 K were studied. The maximum sensor sensitivity of the studied phosphors reached up to 1.16% K À 1 at 523 K. These achievements revealed that Eu 3þ-activated Ca 3 Mo 0.2 W 0.8 O 6 phosphors were promising candidates for solid-state lighting and thermometer.
Ca2Al3O6F:Eu2+: a green-emitting oxyfluoride phosphor for white light-emitting diodes
Journal of Materials Chemistry, 2012
A novel green-emitting phosphor Ca 2 Al 3 O 6 F:Eu 2+ was synthesized and its photoluminescence (PL) properties were investigated for application in white light-emitting diodes (w-LEDs). This phosphor shows good absorption ranging from the ultraviolet to the blue region and a broad green emission band centered at 502 nm. The concentration quenching mechanism and fluorescence lifetime of Eu 2+ emission in the Ca 2 Al 3 O 6 F:Eu 2+ phosphors have been investigated. The key parameters for the fabrication of w-LED lamps, such as the temperature-dependent photoluminescence, microstructure and morphology, CIE value and quantum efficiency of Ca 2 Al 3 O 6 F:Eu 2+ phosphors, have also been studied. The above results indicate that Ca 2 Al 3 O 6 F:Eu 2+ is a good candidate as a green component for near UV-excited w-LEDs.
Indonesian Journal of Electrical Engineering and Computer Science, 2022
We used solid-condition processes to make a sequence of radiationadjustable phosphors Eu 2+ /Mn 2+ co-doped Ca9La(PO4)7 (shortened as CaLa:EM), which show a consistently variable hue from green to yellow and red via an efficient resonance-form energy transition as well as the strength of green and red radiations may be controllable through altering the Mn 2+ concentration. We examined the transition of energy (Eu 2+ → Mn 2+) for CaLa:EM. It is proved to be a resonant kind using a dipole-quadrupole process, having power shift critical range calculated to be 11.36 Å by using the spectral overlap techniques. Mixing a 365 nm UV-InGaN chip as well as one phosphor combination containing (Ca0.98Eu0.005Mn0.015)9La(PO4)7 in yellow with BaMgAl10O17:Eu 2+ in blue produced a warming WLED having CIE color coordinates measured at (0.35, 0.31), better CRI value (Ra) measured at 91.5 along with smaller CCT value of 4,496 K.
Applying green Ca2Al3O6F:Eu2+ oxyfluoride phosphorusonwhite emitting diodes
Indonesian Journal of Electrical Engineering and Computer Science, 2022
Ca2Al3O6F:Eu2+, a new green-emitting and its photoluminescence (PL) characteristics for white lighting-emitting diodes (w-LEDs), have beenanalyzed and generated. This phosphorus displays a strong absorption rangebetween ultraviolet (UV) and blue region, along with a wide green emissionrange of 502 nm. The procedure for concentration suppression and Eu2+ luminous longevity has been investigated using Ca2Al3O6F:Eu2+ phosphors. Key characteristics for manufacturing w-LED lamps, such as photoluminesce based on temperature, microstructure, morphology, CIEvalue and quantum efficiency, were also investigated in Ca2Al3O6F:Eu2+. The findings show that Ca2Al3O6F:Eu2+, is a suitable option for almost UV- excited w-LEDs as a green component.
Bulletin of Electrical Engineering and Informatics, 2022
The study uses the green phosphor of Ca2SiO4:Eu2+ to achieve the color constancy for the dual-film remote phosphor white-LED model at low as well as big CCTs. The utilized green phosphor Ca2SiO4:Eu2+ was prepared using the water-soluble-silicon liquid phase precursor method with the doped Eu2+ ion concentration of 3 mol%. The Ca2SiO4:Eu2+ phosphor emits strong green light with emission intensity focused at 502 nm wavelength, and a wide stimulation band of colors of 225 nm – 450 nm. After applying the Ca2SiO4:Eu2+ green phosphor and modifying its concentration, the modified color and luminous performances can be observed. The better color uniformity and higher luminescence efficiency can be obtained by increasing the percentage of Ca2SiO4:Eu2+ in the phosphor configuration. Meanwhile, the color rendering metrics tend to reduce slightly when the concentration of Ca2SiO4:Eu2+ is over 10% wt.