Dataset Information

Highly Luminous N^3--Substituted Li₂MSiO_4-?N_2/3?:Eu²⁺ (M = Ca, Sr, and Ba) for White NUV Light-Emitting Diodes.

ABSTRACT: The N^3--substituted Li₂MSiO₄:Eu²⁺ (M = Ca, Sr, and Ba) phosphors were systematically prepared and analyzed. Secondary-ion mass spectroscopy measurements revealed that the average N^3- contents are 0.003 for Ca, 0.009 for Sr, and 0.032 for Ba. Furthermore, the N^3- incorporation in the host lattices was corroborated by infrared and X-ray photoelectron spectroscopies. From the photoluminescence spectra of Li₂MSiO₄:Eu²⁺ (M = Ca, Sr, and Ba) phosphors before and after N^3- doping, it was verified that the enhanced emission intensity of the phosphors is most likely due to the N^3- doping. In Li₂MSiO₄:Eu²⁺ (M = Ca, Sr, and Ba) phosphors, the maximum wavelengths of the emission band were red-shifted in the order Ca < Ba < Sr, which is not consistent with the trend of crystal field splitting: Ba < Sr < Ca. This discrepancy was clearly explained by electron-electron repulsions among polyhedra, LiO₄-MO _n , SiO₄-MO _n , and MO _n -M'O _n associated with structural difference in the host lattices. Therefore, the energy levels associated with the 4f⁶5d energy levels of Eu²⁺ are definitely established in the following order: Li₂CaSiO₄:Eu²⁺ > Li₂BaSiO₄:Eu²⁺ > Li₂SrSiO₄:Eu²⁺. Furthermore, using the Williamson-Hall (W-H) method, the determined structural strains of Li₂MSiO₄:Eu²⁺ (M = Ca, Sr, and Ba) phosphors revealed that the increased compressive strain after N^3- doping induces the enhanced emission intensity of these phosphors. White light-emitting diodes made by three N^3--doped phosphors and a 365 nm emitting InGaN chip showed the (0.333, 0.373) color coordinate and high color-rendering index (R _a = 83). These phosphor materials may provide a platform for development of new efficient phosphors in solid-state lighting field.

SUBMITTER: Kim D

PROVIDER: S-EPMC6648572 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Highly Luminous N3--Substituted Li2MSiO4-δN2/3δ:Eu2+ (M = Ca, Sr, and Ba) for White NUV Light-Emitting Diodes.

Kim Donghyeon D Ji Choon Woo CW Lee Jungjun J Bae Jong-Seong JS Hong Tae Eun TE Ahn Sung Il SI Chung In I Kim Seung-Joo SJ Park Jung-Chul JC

ACS omega 20190513 5

The N3--substituted Li2MSiO4:Eu2+ (M = Ca, Sr, and Ba) phosphors were systematically prepared and analyzed. Secondary-ion mass spectroscopy measurements revealed that the average N3- contents are 0.003 for Ca, 0.009 for Sr, and 0.032 for Ba. Furthermore, the N3- incorporation in the host lattices was corroborated by infrared and X-ray photoelectron spectroscopies. From the photoluminescence spectra of Li2MSiO4</sub ...[more]

PMID: 31459932

Similar Datasets

Project description:Eu3+-activated Ba2Y5B5O17 (Ba2Y5-x Eu x B5O17; x = 0.1-1) red-emitting phosphors were synthesized by the conventional high temperature solid-state reaction method in an air atmosphere. Powder X-ray diffraction (XRD) analysis confirmed the pure phase formation of the as-synthesized phosphors. Morphological studies were performed using field emission-scanning electron microscopy (FE-SEM). The photoluminescence spectra, lifetimes, color coordinates and internal quantum efficiency (IQE) as well as the temperature-dependent emission spectra were investigated systematically. Upon 396 nm excitation, Ba2Y5-x Eu x B5O17 showed red emission peaking at 616 nm which was attributed to the 5D0 → 7F2 electric dipole transition of Eu3+ ions. Meanwhile, the influences of different concentrations of Eu3+ ions on the PL intensity were also discussed. The optimum concentration of Eu3+ ions in the Ba2Y5-x Eu x B5O17 phosphors was found to be x = 0.8. The concentration quenching mechanism was attributed to the dipole-dipole interaction and the critical distance (R c) for energy transfer among Eu3+ ions was determined to be 5.64 Å. The asymmetry ratio [(5D0 → 7F2)/(5D0 → 7F1)] of Ba2Y4.2Eu0.8B5O17 phosphors was calculated to be 3.82. The fluorescence decay lifetimes were also determined for Ba2Y5-x Eu x B5O17 phosphors. In addition, the CIE color coordinates of the Ba2Y4.2Eu0.8B5O17 phosphors (x = 0.653, y = 0.345) were found to be very close to the National Television System Committee (NTSC) standard values (x = 0.670, y = 0.330) of red emission and also showed high color purity (∼94.3%). The corresponding internal quantum efficiency of the Ba2Y4.2Eu0.8B5O17 sample was measured to be 47.2%. Furthermore, the as-synthesized phosphors exhibited good thermal stability with an activation energy of 0.282 eV. The above results revealed that the red emitting Ba2Y4.2Eu0.8B5O17 phosphors could be potential candidates for application in near-UV excited white light emitting diodes.

Dataset Information

Highly Luminous N^3--Substituted Li₂MSiO_4-?N_2/3?:Eu²⁺ (M = Ca, Sr, and Ba) for White NUV Light-Emitting Diodes.

Publications

Highly Luminous N<sup>3-</sup>-Substituted Li<sub>2</sub>MSiO<sub>4-δ</sub>N<sub>2/3δ</sub>:Eu<sup>2+</sup> (M = Ca, Sr, and Ba) for White NUV Light-Emitting Diodes.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Highly Luminous N3--Substituted Li2MSiO4-?N2/3?:Eu2+ (M = Ca, Sr, and Ba) for White NUV Light-Emitting Diodes.

Publications

Highly Luminous N<sup>3-</sup>-Substituted Li<sub>2</sub>MSiO<sub>4-δ</sub>N<sub>2/3δ</sub>:Eu<sup>2+</sup> (M = Ca, Sr, and Ba) for White NUV Light-Emitting Diodes.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Highly Luminous N^3--Substituted Li₂MSiO_4-?N_2/3?:Eu²⁺ (M = Ca, Sr, and Ba) for White NUV Light-Emitting Diodes.