Van Liem Bui
Industrial University of Ho Chi Minh City

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The impacts of (Ba,Sr)3BP3O12:Eu2+ on the luminous flux of phosphor-converted-white light emitting diode packages Van Liem Bui; Dieu An Nguyen Thi
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 2: August 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v27.i2.pp685-691

Abstract

The use of (Ba,Sr)3BP3O12:Eu2+ in the remote phosphor structure has been proposed and analysed to offer significant improvement to the lighting performance of the phosphor-converted white light emitting diode (LED). The phosphor emits green and blue spectra centred at 520 nm and 465 nm, respectively. Thus, the phosphor can compensate the blue and green light energy components in the white-light spectral band, helping to enhance the luminous efficiency and colour uniformity of the dual-layer remote phosphor package. The increase in (Ba,Sr)3BP3O12:Eu2+ however is not advantageous to the colour rendering index because of the lower red emission. The backscattered and back-reflected lights are degraded when the (Ba,Sr)3BP3O12:Eu2+ phosphor layer appears in the structure. The stable chromaticity and luminous flux at good values are observed when 10% weight percentage of (Ba,Sr)3BP3O12:Eu2+ is applied.
Applying the green Ca2Al3O6F:Eu2+ oxyfluoride phosphorus on white emitting diodes Van Liem Bui; Dieu An Nguyen Thi
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 2: August 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v27.i2.pp754-759

Abstract

Ca2Al3O6F:Eu2+, a new green-emitting and its photoluminescence (PL) characteristics for white-emitting diodes, have been analyzed and generated (w-LEDs). This phosphorus displays a strong absorption range between ultraviolet (UV) and blue region, along with a wide green emission range 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, CIE value 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.
The effects of SiO2@Y2O2S:Eu3+ phosphor on the optic characteristics of white light-emitting diodes Van Liem Bui; Phan Xuan Le
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 2: August 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v27.i2.pp678-684

Abstract

The study investigated the effectiveness of coating silica nanoparticles (SiO2) and resin-silica nanocomposites poly methyl methacrylate (PMMA)-silicaover the surface of Y2O2S:Eu3+ red phosphors. The purpose of this surface coating is to enhance the optical properties, including the photoluminescence (PL) and long-term stability, of Y2O2S:Eu3+. Two methods used to coat the phosphor with 5-mm silica nanoparticles are dip-coating and sol-gel (Stöber) methods. SiO2 nanoparticles were formed via hydrolysis and condensation reactions, while radical polymerization was performed to fabricate the poly (1-vinyl-2-pyrrolidone). The Y2O2S:Eu3+ surface coating of PMMA-silica composite was performed via two reactions. One is the reaction of SiO2 nanoparticles with methyl methacrylate (MMA) monomer, and the other is MMA-tetraethyl orthosilicate (TEOS) reaction. The results showed that by using the latter method, Y2O2S:Eu3+ yielded better PL and long-term stability. Additionally, surface coating with the PMMA-SiO2 nanocomposite using the second technique resulted in 5% enhancement in PL and stabilized the cathode luminescence (CL) intensity of Y2O2S:Eu3+, compared to those properties of uncoated Y2O3S:Eu3+ phosphor particles.
Ca7Si2P2O16:Eu2+ green phosphor for optic enhancement of the WLEDs dual-layer remote structure Van Liem Bui; Guo Feng Luo; Tam Nguyen Kieu
Bulletin of Electrical Engineering and Informatics Vol 11, No 4: August 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v11i4.4066

Abstract

To enhance the dual-layer remote phosphorus configuration’s color standard help spread its application in the LED devices, the new green-emitting phosphor of Ca7Si2P2O16:Eu2+ is proposed. The sol-gel method is used to dope the Eu2+ ions with Ca7Si2P2O16. Increasing the ion Eu2+ concentration can lead to high thermal stability, color-tunable ability, stronger green emission band, and higher photoluminescence extraction. The dual-layer structure’s color standards, as well as the luminous flux, are examined with different concentrations of Ca7Si2P2O16:Eu2+ in the phosphor layer. Owing to the improved features, the green phosphor Ca7Si2P2O16:Eu2+ has enhanced the emission intensity in the blue and green wavelengths, resulting in better color mixing and distribution. The luminescence shows the enhancement when increasing the concentration of Ca7Si2P2O16:Eu2+. However, the color rendering feature can present a reduction with more than 10% wt. green phosphor within the double-layer phosphorus remote configuration, due to color balance’s loss.
The luminescence efficiency of green phosphor Ca7(PO4)2(SiO4)2:Eu2+ for white light-emitting diode Van Liem Bui; Phan Xuan Le
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 2: August 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v27.i2.pp773-779

Abstract

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 photoluminescent investigation of proposed phosphor composition was monitored under near UV excitation wavelength of the LED die. The sample phase was determined using XRD. To explore Ca7(PO4)2(SiO4)2:Eu2+ capabilities, the diffuse reflectance and photoluminescence 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.