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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.
Performance of ZnS and ZnSe Doped on Cu2+ for Photovoltaic Devices Thuy, Le Xuan; Thanh Tung, Ha; Dat, Le Tien; Le Minh Nhan
Science and Technology Indonesia Vol. 10 No. 3 (2025): 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.2025.10.3.952-957

Abstract

This study utilizes passive ZnS@Cu2+ and ZnSe@Cu2+ layers deposited on the CdS and CdSe quantum dots to reduce dark current and enhance photon absorption. The films were fabricated utilizing the successive ionic layer adsorption and reaction technique with an optimized and suitable Cu/Zn doping ratio. Ultraviolet–visible spectroscopy, X-ray diffraction, and field emission scanning electron microscopy analyses indicate a change in the absorption edge within the visible light region when ZnS and ZnSe are doped with Cu2+ ions. Power conversion efficiency measurements reveal that the ZnSe@Cu2+ photoelectrode increases the current density (JSC ~23 mA.cm-2) compared to ZnS@Cu2+ The photoelectrode exhibits a short-circuit current density (JSC ≈ 22 mA · cm−2), leading to improved conversion efficiency. It also shows the lowest charge transfer resistance (Rct2 = 33 − Ω), indicating efficient interfacial kinetics in the photoelectrode suggests more efficient electron transport and reduced recombination.