MxLa1- xSiO2- yNz(M = Ca/Sr/Ba): Elucidating and Tuning the Structure and Eu2+Local Environments to Develop Full-Visible Spectrum Phosphors
Journal
Chemistry of Materials
Date Issued
2022
Author(s)
Abstract
The local environments of rare-earth activators have profound effects on the luminescent properties of phosphors. Here, we elucidate the crystal structure of the LaSiO2N phosphor host using a combination of density functional theory calculations and synchrotron X-ray diffraction. We determine that LaSiO2N crystallizes in the monoclinic C2/c instead of the hexagonal P6¯ c2 space group. To improve the luminescence performance, divalent cations M (M = Ca/Sr/Ba) were introduced into LaSiO2N to eliminate Eu3+. A family of apatite M1+xLa4-xSi3O13-x/2:Eu2+ (x ∼1.5, M = Ca/Sr/Ba) phosphors was further developed with unprecedented ultra-broadband (290 nm) emission spectra and excellent thermal stability. Detailed local environment investigations reveal that the formation of oxygen vacancies within and beyond the first-shell environment of Eu2+ is responsible for the redshift and broadening of the emission spectra via geometrical alteration of the Eu2+ local environment. This work provides new insights for understanding and optimizing the luminescence of rare-earth phosphors. © 2022 American Chemical Society.
SDGs
Other Subjects
Barium compounds; Crystal structure; Density functional theory; Emission spectroscopy; Europium compounds; Luminescence; Phosphate minerals; Phosphors; Rare earths; Silicon; Silicon compounds; Strontium compounds; Crystals structures; Density-functional theory calculations; Emission spectrums; Local environments; Luminescent property; Monoclinics; Rare-earth activators; Space Groups; Visible spectrums; X- ray diffractions; Lanthanum compounds
Type
journal article