Phuc Dang Huu
Industrial University of Ho Chi Minh City

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Journal : Bulletin of Electrical Engineering and Informatics

The effects of silica-coated Y2O2S:Eu3+ red phosphor on the lighting properties of the light-emitting diode Phuc Dang Huu; Phan Xuan Le
Bulletin of Electrical Engineering and Informatics Vol 11, No 4: August 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v11i4.4063

Abstract

The red phosphor Y2O2S:Eu3+ coated with silica (SiO2) nanocomposite was synthesized using the sol-gel method with dip-coating technique. The purpose of coating the poly (methyl methacrylate) (PMMA)-SiO2 composite on Y2O2S:Eu3+ phosphor’s surface is to protect the phosphor and improve its scattering ability. The three primary ingredients of coating composition include methyl methacrylate (MMA) monomer, tetraethyl orthosilicate (TEOS), and SiO2 nanoparticles. Via Mie scattering theory, the scattering of SiO2 is examined, which primarily determines the scattering of PMMA-SiO2-coated Y2O2S:Eu3+. The larger particles of SiO2 in the coating composite leads to better scattering properties. When being applied in the dual-film remote phosphor configuration of a LED, SiO2@Y2O2S:Eu3+ considerably enhances the CRI and the color quality scale (CQS). The highest CRI and CQS can be observed at approximately 85 and 74 with 23 %wt. and 26 %wt. the concentration of SiO2@Y2O2S:Eu3+, respectively. Neverthless, the illuminating beam of the package gradually declines as the concentration of SiO2@Y2O2S:Eu3+ go up, which might be ascribed to excessive scattering occurrences in the double-layer remote package.
SiO2@LaOF:Eu3+ in white light emitting diodes optic efficiency enhancement Phuc Dang Huu; Guo Feng Luo; Minh Pham Quang
Bulletin of Electrical Engineering and Informatics Vol 11, No 4: August 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v11i4.4065

Abstract

The earliest intense red hue compound of SiO2@LaOF:Eu3+ core-shell nanostructures (NS) was created utilizing a basic solvothermal technique and heat processing. The produced core-shell particles are spherical, non-agglomerated, and have restricted size dispersion. Photoluminescence (PL) radiation spectra exhibit sharp maximums in 593, 611, and 650 nm, corresponding with 5D0 -- more than 7FJ (J=0, 1, 2) Eu3+ conversions. The Judd-Ofelt (J-O) hypothesis helps determine the spectrum strength indices and Eu-O ligand activities. The CIE coordinates are x=0.63, y=0.36, nearly equal the NTSC coordinates which are x=0.67, y=0.33. Because of the CCT level of 3475 K, which is lower than 5000 K, this phosphor is appropriate for warm light-emitting diodes. To visualize latent fingermarks both porous and non-porous substrates, the fluorescent labeling marker adapted core-cover SiO2 (coat III)@LaOF:Eu3+ (5 mol%) was utilized. With no background influence, the fingermarks obtained are exceedingly sensible and exclusive, permitting for fingerprint ridge features ranging from level-I to level-III. The findings indicate the significant enhancement in the illumination of corecover NS as a responsive operational nanoparticle for increased forensics and firm status illuminating implementations.