Linking Macro- And Micro-structural Analysis with Luminescence Control in Oxynitride Phosphors for Light-Emitting Diodes
Publication Name
Chemistry of Materials
Abstract
Eu2+-doped UCr4C4-type oxynitride phosphors are emerging innovative materials to replace oxide and nitride phosphors for high-end light-emitting devices. However, the synthesis of high-purity phosphors and controlling the O/N ratio remain challenging. Here, we synthesized a series of Sr0.98Li2.5 + zAl1.5 - zO3 + 2zN1 - 2z:0.02Eu phosphors by precursor engineering, and these products showed an unexpected redshift from 583 to 620 nm. Joint refinement combining synchrotron X-ray diffraction and neutron powder diffraction was conducted to determine macro-structural properties. Extended X-ray absorption fine structure spectra revealed the micro-structural properties around the luminescent centers. The effects on photoluminescence from the first-shelled O/N ligands and the second-shelled Li/Al ions were demonstrated in detail. Finally, the light-emitting diode packages constructed using our phosphor revealed higher luminous efficiency of radiation and luminous efficacy than the SrLiAl3N4:Eu comparator. This study provided the basis for developing novel oxynitride phosphors and insights into the structural analysis from the macro and micro perspectives.
Open Access Status
This publication is not available as open access
Volume
33
Issue
19
First Page
7897
Last Page
7904
Funding Number
2016/23/B/ST3/03911
Funding Sponsor
Ministry of Science and Technology, Taiwan