My Hanh Nguyen Thi
Industrial University of Ho Chi Minh City

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Journal : Indonesian Journal of Electrical Engineering and Computer Science

Color-adjustable phosphors Sr4La(PO4)3O:Ce3+,Tb3+,Mn2+ impact on luminescence of white light-emitting diodes My Hanh Nguyen Thi; 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.pp728-734

Abstract

We used the ceramic approach to synthesize a sequence of Sr4La(PO4)3O:Ce3+,Tb3+,Mn2+ within our study. Especially, the attributes of Sr4La(PO4)3O that were extensively investigate are luminous characteristics, thermal stableness, and energy transfering from Ce3+ to Tb3 and Mn2+.Through energy transfer, sensitizer Ce3+ ions can considerably boost the fragile green radiation from Tb3+ and red radiation from Mn2+. The color of the radiation can be changed by adjusting the Ce3+/Tb3+ and Ce3+/Mn2+ ion ratios. The Sr4La(PO4)3O: 0.12Ce3+, 0.3Mn2+ specimen produced white light having hue coordinates of (0.3326, 0.3298). According to this result, it shows that Sr4La(PO4)3O:Ce3+,Tb3+,Mn2+ might be used in white light-emitting diodes (WLEDs).
Luminescence and transfer for power characteristics of Sr4La(PO4)3O:Ce3+,Tb3+,Mn2+ phosphor for WLEDs My Hanh Nguyen Thi; 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.pp722-727

Abstract

We apply the high-heat solid-state technique to create a sequence of phosphors Sr4La(PO4)3O:Ce3+,Tb3+,Mn2+. In Sr4La(PO4)3Othe luminescence characteristics, heat resistance, and transfer of energy between Ce3+ and Tb3+ as well as Mn2+ were thoroughly studied. The insertion of the sensitizer Ce3+ ions can significantly flatter the emission of the color green from Tb3+ and the emission of the color red from Mn2+ via energy transfer. By modifying the Ce3+/Tb3+ and Ce3+/Mn2+ ion ratios, it can change the emission color. White light, which has color coordinates of 0.3326, 0.3298, were produced by the Sr4La(PO4)3O: 0.12Ce3+, 0.3Mn2+ 0.12Ce3+, 0.3Mn2+ specimen, showing Sr4La(PO4)3O:Ce3+,Tb3+,Mn2+ might be profitable in white LEDs.
Utilizing a strait-range green phosphor γ-AlON:Mn,Mg for the task of achieving a super-broad hue gamut display My Hanh Nguyen Thi; 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.pp748-753

Abstract

The screen backlighting produced by green β-sialon:Eu, as well as red K2SiF6:Mn phosphors, have an extremely expansive hue gamut that encompasses the majority of the national television system committee (NTSC) triangle. For our research, a substitute phosphor in green would be probed in terms of improving the screen hue range even further. The phosphor γ-AlON:Mn,Mg appears to be green in color with a smaller radiation band of colors than sharp β-silaon:Eu. By replacing γ-AlON:Mn,Mg with β-sialon:Eu, the screen hue range in the blue-green area is significantly expanded. In both the CIE 1931 and CIE 1976 hue spaces, the hue range of screens with γ-AlON:Mn,Mg, and K2SiF6:Mn entirely surpasses the NTSC benchmark. Furthermore, the stability of LEDs emit white light using γ-AlON:Mn,Mg appears to be similar to LEDs that utilize β-sialon:Eu.
The application of phosphor Sr4La(PO4)3O:Ce3+,Tb3+,Mn2+ on white light-emitting diodes My Hanh Nguyen Thi; Phan Xuan Le
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v27.i3.pp1251-1257

Abstract

Using a high temperature solid-state technique, various phosphors Sr4La(PO4)3O:Ce3+, Tb3+,Mn2+ (SLPO:Ce,Tb,Mn) were produced. In Sr4La(PO4)3O, the luminescence characteristics, thermal stability, and energy conversion between Ce3+ and Tb3+-Mn2+ have been thoroughly studied. The sensitizer Ce3+ particles inclusion could considerably improve the feeble Tb3+ green radiation and Mn2+ red radiation via energy transfer. By adjusting the scale of Ce3+/Tb3+ over Ce3+/Mn2+ atoms, the color of the emission may be changed. White light was produced in the Sr4La(PO4)3O:0.12Ce3+,0.3Mn2+ specimen with chromatism coordinates of (0.3326, 0.3298), showing that the phosphors SLPO:Ce,Tb,Mn possess promising application on WLEDs. The conclusion is supported by Mie-scattering theory and Lambert-Beer's law.
High stability in color chromaticity of warm white emitting diode with dual-hue SrSi2O2N2:Eu2+,Yb2+ phosphor My Hanh Nguyen Thi; Phan Xuan Le; Nguyen Le Thai
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v27.i3.pp1258-1263

Abstract

In this study, we analyzed and developed a phosphor with a nitridiosilicate based and emitting color changing from green to orange to apply to our white-light-emitting diodes (WLEDs). Eu2+ and Yb2+ trap sites of two-doped SrSi2O2N2:Eu2+,Yb2+ (SrYb) nitridosilicate emit a wide emission in the region between green and orange. Through calculating the decompose time of the green-emission power donor, we could determine the converted energy between the active ions. Furthermore, we also analyzed the impact of co-doping with varied active ion ratios on the photoluminescence (PL) characteristics. As the concentration of Yb2+ increases, the red emission dominates the green. This was because the obtained phoshor's emission depended on the activator ion components. To generate white light, a combination of the acquired phosphor and the InGaN blue LED chip with a 450 nm wavelength was used. With only two steps, we could detect the hue balance management. Firstly, by modifying the Eu2+ and Yb2+ concentration, we can conduct a green-to-orange proportion optimization. Following that, the commission onillumination (CIE) coordinates were transformed to [0.4071; 0.3789] from the original position, which was [0.2805; 0.2014] by enhancing the phosphor powder amount. An environment which has a CRI of around 89 is the optimum condition for conducting white light.
Enhancement of luminous efficacy for light-emitting diodes lamps by adding CaSr2(PO4)2:Eu3+ phosphor Ho Minh Trung; My Hanh Nguyen Thi
Indonesian Journal of Electrical Engineering and Computer Science Vol 31, No 3: September 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v31.i3.pp1328-1333

Abstract

Through employing the fluid ignition technique, we created the samples CaSr2(PO4)2:Eu3+ with Eu3+ incorporated then assessed them in the form of contactless optical heat measurement as well as solid-state illumination. We identified the attributes for these samples including X-ray diffraction (XRD), photoluminescent spectroscopy, Fourier transmute infrared spectroscopy (FTIS) along with photoluminescent spectroscopy correlating with temperature. XRD, along with FTIS, validates that the one-stage samples were formed via the orthophosphate anion (PO4)3- . In the case of these samples, nUV recreation under 395 nm generated potent, orange-red discharge lines under 592 nm as well as 615 nm, which is consistent with the standard shifts between 5D0 and 7F1 as well as 5D0 and 7F2 for the Eu3+ ions. The International Commission on Illumination (CIE) coordinates (0.65, 0.35) based on the hue scale validate the red discharge. For the task of attaining optical heat measurement, we took advantage of the fluorescent intenseness proportion technique that utilizes heat-incorporated discharge states of 5D1 as well as 5D0 for Eu3+ . The samples have maximum responsiveness reaching roughly 0.0023 K-1 under 323 K or small heat levels. According to the outcomes, it is possible to utilize the samples when it comes to contactless optical heat measurement as well as solid-state illumination.