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All Journal International Journal of Advances in Applied Sciences Science and Technology Indonesia Indonesian Journal of Electrical Engineering and Computer Science
Cong, Pham Hong
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Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Earth & Planetary Sciences Environmental Science Materials Science & Nanotechnology Mathematics Physics

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Journal : Science and Technology Indonesia

 1 
Application of KBaYSi2O7:Bi3+,Eu3+ Phosphor for White Light-Emitting Diodes with Excellent Color Quality Loan, Nguyen Thi Phuong; Thuy, Le Xuan; Thai, Nguyen Le; Lee, Hsiao Yi; Cong, Pham Hong
Science and Technology Indonesia Vol. 9 No. 3 (2024): July
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.2024.9.3.756-765

Abstract

This paper examines the properties of two phosphor materials synthesized via utilizing the sol gel method: KBaYSi2O7:Bi3+ (KBYS:Bi) phosphor providing cyan/deep-blue emission and KBaYSi2O7:Bi3+,Eu3+ (KBYS:Bi,Eu) phosphor exhibiting tunable emission from near-UV to red. The optimal doping concentrations for Bi3+ and Eu3+ are 0.2% and 3.5%, respectively. It is found that the ability to give discrepant emission peaks under different excitation sources of the KBYS:Bi phosphor is attributed to the occupancy of Bi3+ in different cation hosts. Meanwhile, co doping the Eu3+ and Bi3+ into the KBYS host leads to red and cyan emission regions, enabling the emission tunability of the KBYS:Bi,Eu phosphor. KBYS:Bi,Eu phosphor was then used in combination with YAG:Ce3+ and blue chips to fabricate a white light emitting diode (LED) model. The particle sizes of KBYS:Bi,Eu phosphor are adjusted to examine its influences on the LED properties. With increasing particle sizes (≥12 µm), the KBYS:Bi,Eu phosphor can improve the scatter efficacy, transmission power, lumen output, and color performance (rendition and uniformity). Both KBYS:Bi and KBYS:Bi,Eu phosphors are promising luminescent phosphors that can be combined with other phosphor with different emission colors to obtain the full-spectrum or tunable white light for LEDs.
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.
Enhancing Scattering Strength Improvement and Color Uniformity in White Light-Emitting Diodes Using High Concentration of Yttrium Oxide Cong, Pham Hong; Loan, Nguyen Thi Phuong; Tung, Ha Thanh
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.2026.11.1.174-181

Abstract

This study investigates the effect of yttrium oxide (Y2O3) doping on the phase evolution of barium titanate (BaTiO3), a key dielectric material used in multilayer ceramic capacitors (MSCCs). Two types of starting powders were examined: pure BaTiO3 and a commercial X7R composition containing 1 wt% Y2O3. Using the solid-state method under high temperature, Y2O3 was added in varying amounts, and the powders were processed under controlled sintering conditions to evaluate its influence on phase formation. The resulting ceramics were characterized to determine formational alterations as well as the potential generation of secondary phases. Increasing Y2O3 content led to a transmutation from the tetragon structure to a merger between tetragon as well as cubic phases. The commercial X7R powder exhibited greater densificating process, surpassing pure BaTiO3 and formed a cuboid formation under greater Y2O3 concentrations. Notably, the sample doped with 20 wt% Y2O3 produced the Ba6Ti17O40 phase, augmenting scattering capacity and color uniformity. These findings clarify the role of Y2O3 in phase evolution and highlight its implications for optimizing BaTiO3-based MSCC materials.
Co-Authors Anh, Nguyen Doan Quoc Duy, Le Doan Le, Phan Xuan Lee, Hsiao Yi Lee, Hsiao-Yi Loan, Nguyen Thi Phuong Thai, Nguyen Le Thuy, Le Xuan Tran, Thinh Cong Trang, Le Thi Tung, Ha Thanh