Claim Missing Document
Check
Articles

Found 5 Documents
Search

Augmenting Chroma Performance for WLED Employing Sr8ZnSc(PO4 )7:Eu2+@SiO2 as a Scattering-Enhancing Substance Cong, Pham Hong; Anh, Nguyen Doan Quoc
Science and Technology Indonesia Vol. 10 No. 2 (2025): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2025.10.2.467-472

Abstract

Featuring the B-Ca3(PO4)2 phosphor system, Sr8ZnSc(PO4)7:Eu2+ (SZSPOE) phosphor can be used as an alternative to YAG:Ce3+ yellow phosphor for the advancement of the white light-emitting diode (WLED). Its potentials are demonstrated in this paper, including the expected emission power and wavelength based on the previous studies and its impacts on WLED illumination properties employing Mie-theory-based scattering simulation and calculation and MATLAB software. SZSPOE phosphor can display a wide yellow discharge peaking at 511 and 571 nm and a redshift upon the increase in doped Eu2+ dosage. A phosphor layer comprised of SZSPOE phosphor, SiO2 particles, and silicone gel is simulated for making a WLED. The WLED performance is observed with varying SiO2 amount. Changes in simulation results of the WLED’s lighting properties can be attributed to the scattering within the phosphor layer in response to different SiO2 concentrations. Results demonstrate that increasing SiO2 amount can lead to the better spatial color distribution uniformity and luminous output of the WLED. Meanwhile, the lower color rendering index is observed owing to the insufficient red light power. However, the improvement in color uniformity and luminosity alongside the emission tunability of the SZSPO host, SZSPOE phosphor can be a promising candidate for substituting the original YAG:Ce3+ for advanced WLEDs.
Computer simulation and software engineering in optical analysis of phosphor-converted white light-emitting diodes utilizing barium sulfate Trang, Le Thi; Loan, Nguyen Thi Phuong; Cong, Pham Hong; Anh, Nguyen Doan Quoc; Lee, Hsiao-Yi
International Journal of Advances in Applied Sciences Vol 14, No 4: December 2025
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijaas.v14.i4.pp1384-1392

Abstract

Achieving uniform nanoparticle dispersion in electrospun polymer nanofibers remains a critical challenge, as conventional electrospinning often leads to particle agglomeration and nozzle clogging, reducing fiber uniformity and functional efficiency. This study explicitly addresses this problem by developing poly (vinyl alcohol) (PVA)/BaSO4 composite nanofibers through both conventional and ultrasonic-assisted electrospinning. Scanning electron microscopy (SEM) revealed that ultrasonication effectively disrupted nanoparticle agglomerates, yielding smoother and more uniform fiber morphologies. X-ray diffraction (XRD) analysis further confirmed that ultrasonic processing reduced the crystalline intensity of PVA and BaSO4, indicating enhanced polymer–filler interaction and finer BaSO4 distribution. Quantitatively, the agglomeration slope decreased from 0.039 (conventional) to 0.006, and the mean crystallite size was reduced from approximately 470 to 300 nm. These results are consistent with recent advances showing that ultrasonic electrospinning improves nanoparticle dispersion and stability in polymer matrices, thereby enhancing optical and mechanical properties. Ultimately, this work demonstrates that ultrasonic-assisted electrospinning provides a robust and scalable strategy to fabricate lightweight, flexible, and multifunctional PVA-based radiation shielding materials with superior nanoparticle dispersion and structural homogeneity.
Influence of potassium bromide phosphor on optical properties of white light-emitting diodes Cong, Pham Hong; Loan, Nguyen Thi Phuong; Anh, Nguyen Doan Quoc; Lee, Hsiao-Yi
International Journal of Advances in Applied Sciences Vol 14, No 4: December 2025
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijaas.v14.i4.pp1359-1366

Abstract

Conventional phosphor-converted light-emitting diodes (LEDs) using silicone binders often suffer from yellowing, moisture degradation, and limited spectral tunability, restricting their performance in high-power street lighting. To overcome these limitations, this study aims to develop an advanced LED illumination system integrating a KBr-doped sol-gel/silica phosphor with total internal reflection (TIR) lenses and a reflective housing, encapsulated by an atomic layer deposition (ALD)-coated minilens panel. The sol-gel matrix, synthesized from MTEOS, TEOS, and silica granules, was engineered to achieve uniform KBr particle dispersion, reduced thermal quenching, and improved chromatic stability. The ALD laminate provides an additional moisture and heat barrier, sealing micro-defects and minimizing stress-induced cracking. Optical performance was quantitatively assessed using Monte Carlo beam-tracking simulations under various street configurations, including focal, zigzag, and single-plane pole layouts. Results demonstrated enhanced luminous efficacy, precise glare control, and high uniformity in street illumination. Overall, this integrated sol-gel/ALD LED design effectively addresses the durability and color instability problems of traditional silicone systems, offering a scalable and energy efficient solution for next-generation street lighting.
Thermally stable sol-gel yttrium aluminum garnet cerium phosphors for white light-emitting diodes Le, Phan Xuan; Loan, Nguyen Thi Phuong; Anh, Nguyen Doan Quoc; Lee, Hsiao-Yi
International Journal of Advances in Applied Sciences Vol 14, No 4: December 2025
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijaas.v14.i4.pp1367-1374

Abstract

This study aims to develop structurally controlled TiO2-based materials that serve a dual purpose as high-performance photocatalysts and optical scattering agents for white light-emitting diodes (LEDs). Hollow spherical TiO2, TiO2/Ag, and TiO2/Au particles were synthesized via a one-step spray thermolysis process using aqueous titanium citrate and titanium oxalate precursors. The method enables precise control of morphology and crystalline phase composition, producing hollow microspheres with tunable anatase–rutile ratios (10–100%) and crystallite sizes ranging from 12 to 120 nm. Photocatalytic performance, evaluated through the ultraviolet (UV) driven oxidation of methylene blue, showed that as-prepared TiO2 exhibited comparable activity to Degussa P25, while metal doping accelerated the anatase-to-rutile transition with minimal plasmonic enhancement under UV light. For LED applications, incorporating hollow TiO2 particles into YAG:Ce phosphor films improved luminous intensity, reaching a peak of ∼71 lm at 1 wt.% TiO2, and enhanced color uniformity, achieving a D-CCT as low as ∼60 K at 5 wt.%. These results confirm that spray thermolysis provides a scalable route to tailor morphology and phase composition, enabling multifunctional TiO2 materials optimized for both environmental photocatalysis and high-quality LED lighting.
Optical Assessment of Titanium Oxide Employed in Phosphor-Transmuted WLED Devices Le, Phan Xuan; Loan, Nguyen Thi Phuong; Anh, Nguyen Doan Quoc
Science and Technology Indonesia Vol. 11 No. 1 (2026): January
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2026.11.1.345-355

Abstract

Utilizing inexpensive PbO-B2O3-SiO2-ZnO glass as the host, a new environmentally friendly method for phosphor-transformed WLED utilizing Ce:YAG-doped glass and Titanium oxide (TiO2) was effectively created for this study. This method demonstrated good sintering behavior and elevated visible transparency with a sintering heat level reaching 750oC while avoiding influence on phosphor samples. The optic characterization of WLED can be simply adjusted by only modifying the temperature, incorporating dosage, as well as sample breadth to suit the mucous sintering for phosphor within glass (PwG). The perfect sample amount is regulated, reaching 5 wt.% of the end combination, and the most suited thickness of samples is discovered to be 0.8 mm. As a consequence, the optimum heating condition is sintered at 700oC within 40 minutes. The built-in PwG WLED displays an elevated illuminating effectiveness of 134.33 lm/W, associated hue temperature of 4696 K, and hue rendering index of 68.5. PwG’s improved heat quenching ability when combined with traditional silicone resin and TiO2 makes it clear that the glass ceramic substance used today is highly practical for use in WLED apparatuses.