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All Journal TELKOMNIKA (Telecommunication Computing Electronics and Control) Bulletin of Electrical Engineering and Informatics Indonesian Journal of Electrical Engineering and Informatics (IJEEI) Indonesian Journal of Electrical Engineering and Computer Science
Phan Xuan Le
Van Lang University
Computer Science & IT Electrical & Electronics Engineering

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Application of CaTiO3:Pr3+ Phosphor for Enhancing the Hue Standard of WLEDs with Double-Film Distant Phosphor Structure Dieu An Nguyen Thi; Phan Xuan Le
Indonesian Journal of Electrical Engineering and Informatics (IJEEI) Vol 10, No 2: June 2022
Publisher : IAES Indonesian Section

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52549/ijeei.v10i2.3236

Abstract

Due to its great thermal stability, the WLEDs (short for white-light diodes), which are made of PiG (short for phosphor-in-glass), appear to be an optical source most effective at generating potent white illumination. However, the actual applications they offer are limited by their poor color rendering and color uniformity. To improve the color rendering and uniformity, this study suggested utilizing a configuration involving a PiG-RPL (short for PiG integrated with a lens of phosphor in red). The phosphor YAGG (also known as Y3Al3.08Ga1.92O12:Ce3+) and borosilicate glass powders were printed, then sintered to generate the green PiG, and then using an inverted dispensing approach, we applied the CASN phosphor silicone in red color (also known as CaAlSiN3:Eu2+) to the said PiG. As a result, with a current of 350 mA, the WLEDs made of PiG-RPL exhibit highly remarkable chromatic performance for the CRI (also known as color rendering index) values determined as Ra = 95.6 with R9 = 95.2 and fidelity/gamut values determined as Rf = 92 with Rg = 99.2. The color quality of the PiG-RPL based WLEDs is steady over a wide range of currents, from 100 to 1000 mA. Moreover, PiG-RPL based WLEDs have better color uniformity than typical PiG based WLEDs. The PiG-RPL structure was proposed in this paper to improve the WLEDs’ chromatic generation as well as chromatic homogeneity. We made the PiGRPL via placing a lens of CASN phosphor above a PiG in green color made of YAGG phosphor. For WLEDs, the PiG-RPL provides extremely remarkable chromatic generation. Furthermore, the WLEDs that are made of PiG-RPL have better color uniformity than those made of PiG and PiG-RPP. The PiG-RPL color converters are considered to be promising for high-power WLEDs, offering great color rendering and color uniformity.
Selection of Gd2(WO4)3:Tb3+ for inproving color deviation in white light-emitting diodes Dieu An Nguyen Thi; Nguyen Doan Quoc Anh; 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.pp709-714

Abstract

This study successfully using the hydrothermal technique to synthesize Gd2(WO4)3:Tb3+ phosphors when subjected to calcination under the temperature of 900°C. Here are some aspects that were thoroughly examined: the crystal formation, photoluminescence, photoluminescence excitation, as well as fluorescent degradation for the samples. The (Gd2-xTbx)(WO4)3 (x=0.01-0.15) phosphors exhibit a bright discharge of green under 547 nm (5D4→7F5 shift for Tb3+) when excited at 270 nm (4f8→4f75d1 shift for Tb3+). Because of the exchange interaction between Tb3+, the quenching concentration was determined to be around 10%. The addition of Tb3+ had no effect on the (Gd2-xTbx)(WO4)3 phosphors' CIE chromaticity coordinates (~0.33±0.02, ~0.60±0.02) or color temperatures (~5542 K). Nevertheless, when the Tb3+ content increased, the fluorescence lifespan for 547 nm emission reduced due to energy transfer between Tb3+. The strong green emission from Gd2(WO4)3:Tb3+ phosphors is a potential element for WLEDs and display areas.
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).
Thermodynamic properties in quantum dot nanocomposite for white light-emitted diodes Phuc Dang Huu; 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.pp632-637

Abstract

For a colour conversion substance, we developed a new nanocomposite containing a CdSe/CdS/ZnS red-emitted quantum dot (QD), a green-emittedd Sr2SiO4:Eu phosphorus, and silicon resins. Regarding QD concentration and ingredients, the heat increase and optic features of the nanocomposite attributable to the QD inclusion were examined. According to the findings, a modest portion of QDs added to a photon converter at the emission wavelength of QD produced a considerable degree of heat. We used 0.2 wt% QDs over an InGaN blue-emitting light-emitted diodes (LED) chip to simulate a thermal increase in a nanocomposite. Consequently, we were able to produce a white-emitted LED module featuring a good 83.2 colour rendered index, an excellent 65.86 lm W-1 brightness, and a reasonable 94 °C thermal rise. The recently founded QD-phosphorus nanocomposite transformed white-emitted LED offers a lot of possibility of modern lighting.
Y2O3:Eu3+ concentration and particle size: their impacts on color rendering index and lumen of multi-chip white diodes Phuc Dang Huu; 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.pp760-765

Abstract

Aiming at achieving higher colour standard for multi-chip white light-emitting diode (MCW-LEDs) through the enhancement of their color rendering index (CRI), this article worked on and proposed a novel MCW-LED package using a compound of red phosphor Y2O3:Eu3+. The red phosphors were synthesized and applied to build both protective coating and in-cup phosphor configurations. The CRI of MCW-LED which has high correlated colour heat of 8,500 K was observed to be heightened to 86. Moreover, the scattering of the light when added the red phosphor Y2O3:Eu3+ is demonstrated using Mie-scattering theory, while the influences of the red-light enhancement is analyzed using the law of Lambert-Beer.
Application of (Ca1-xSrx)LaGa3S6O:Eu2+ phosphor in white light-emitting fabrication Dieu An 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.pp735-740

Abstract

An alternating sequence of Ca1-xSrxLaGa3S6O:0.05Eu2+ phosphors was produced using high-thermal and solid-state reactions. It has outstanding excitations at the range between 350 and 500 nm suitable for the close-ultraviolet or GaN-based blue LED chips. These phosphor peaks have a blue shift between 560 and 540 nm when the Sr concentration (x) rises. The Sr content (x) can be modified to produce an illumination with a color between yellow and green. As a result, we can conclude that solid solutions Ca1-xSrxLaGa3S6O:0.05Eu2+ are excellent for use in manufacturing white LEDs. Our data may become valuable for producers in the task of making white light emitting diode (WLED) devices suitable for them.
Effects of titanium dioxide quantum dots on the color deviation and luminous flux of white light-emitting diodes Thanh Binh Ly; Phung Ton That; 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.pp611-617

Abstract

The application of quantum dots has been considered as a promising approach to the advancement of phosphor-converted light-emitting diodes (pc-LEDs) since they perform an excellent extinction coefficient. Yet, it is challenging to manage their influences on the optical properties of LEDs due to their different nanometers in size. Hence, the object of this research is to analyze the influences of quantum dot (QDs) to figure out the solution to control the enhancement of LED lighting performances. Particularly, the study worked on investigating the scattering and absorption features of titanium dioxide (TiO2) QDs. It demonstrated that the radiant efficiency and luminous stability of the TiO2 QDs-converted LEDs (QC-LEDs) was inferior due to the strong light absorption and reabsorption occurring inside the LED packages. Additionally, it also presented low uniformity of color distribution because the scattering ability of QDs is weak. Therefore, reducing the concentration of QDs when adding to the LED structure seems to be possible to enhance the luminous output of QC-LEDs. We propose 0.05% wt. TiO2 for white LED to reduce the illumination losing caused by re-absorbent and total internal backscattering, resulting in approximate 31% lumen improvement and high color rendering index (CRI) measured at about 85, at a high color temperature of 7500 K.
Utilizing the right phosphor in near-ultraviolet and blue light-emitting diode devices to generate white illumination Dieu An Nguyen Thi; Nguyen Doan Quoc Anh; 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.pp715-721

Abstract

In the scenario of solid-state lighting (SSL) gradually replacing old standard techniques; the pc-LEDs (or diodes based on conversion phosphor) becomes a common method for creating white illumination, based on SSL. As of now, both of the UV-LEDs and the blue LEDs have been still being considered for the task of creating white illumination through phosphor excitation as it hasn’t been known which LED type is truly superior. It is common that when it comes to phosphor, people will overlook the performance in LED devices with a wavelength range of 365 nm to 470 nm. Our research demonstrates the information concerning extrinsic quantum efficacy in the InxGa1-xN LED devices with the mentioned range as well as combines the information and the effectiveness of phosphor for the task of examining the performance of near-UV and blue LEDs and creating white illumination. In addition, the research demonstrates recreations for the task of assessing the white illumination mixtures under the correlated color temperature of 3000 K and 4000 K in the two LED structures.
High-efficiency green and red phosphors enable a broader hue-gamut light-emitting diode backlight for brighter displays Dieu An 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.pp741-747

Abstract

In this article, we suggest combining a blue InGaN chip with strait-band green (β-sialon:Eu2+), red (K2SiF6:Mn4+) phosphors to create WLED devices with a wide hue range and high effectiveness that may be utilized in LCD backlighting. The highest radiation wavelength of a gas-pressure sintedβ-sialon:Eu2+ is 535 nm, the full width at half maximum (FWHM) is 54 nm, and the outside quantum performance is 54.0% lower than the 450 nm stimulation. We created K2SiF6:Mn4+ in two steps. The phosphor possesses a sharp line radiation spectrum accompanied by the most intense maximum point under 631 nm, an FWHM reaching roughly 3 nm, as well as an exterior quantum effectiveness of 54.5%. When computed at 120 mA, the manufactured three-range wLEDs had an illuminating performance of 91–96 lm/W and a large color temperature of 11,184–13,769 K (i.e., 7,828–8,611 K in LCD screens). The hue range represented by the CIE 1931 and CIE 1976 hue gaps is 85.5-85.9% and 94.3-96.2% of the NTSC requirement, respectively.  The optic characteristics outperform those of phosphor-transformed wLED backlights utilizing broad-range green or red phosphors, indicating the two strait-range phosphors studied are the best luminous substances for producing brighter and livelier screens.
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.
Co-Authors Dieu An Nguyen Thi Dieu An Nguyen Thi Dieu An Nguyen Thi Dieu An Nguyen Thi Le Hung Tien Le Nguyen Hoa Binh Le Tien My Hanh Nguyen Thi Nguyen Doan Quoc Anh Nguyen Le Thai Nguyen Thi Phuong Loan Pham Quang Minh Phuc Dang Huu Phuc Dang Huu Phuc Dang Huu Phung Ton That Phung Ton That Phung Ton That Thanh Binh Ly Tran Thanh Trang Van Liem Bui Van Liem Bui