Improvement of the Water Resistance of a Narrow-Band Red-Emitting SrLiAl3N4:Eu2+Phosphor Synthesized under High Isostatic Pressure through Coating with an Organosilica Layer
Journal
Angewandte Chemie - International Edition
Journal Volume
55
Journal Issue
33
Pages
9652-9656
Date Issued
2016
Author(s)
Abstract
A SrLiAl3N4:Eu2+(SLA) red phosphor prepared through a high-pressure solid-state reaction was coated with an organosilica layer with a thickness of 400–600 nm to improve its water resistance. The observed 4f65d→4f7transition bands are thought to result from the existence of Eu2+at two different Sr2+sites. Luminescence spectra at 10 K revealed two zero-phonon lines at 15377 (for Eu(Sr1)) and 15780 cm−1(for Eu(Sr2)). The phosphor exhibited stable red emission under high pressure up to 312 kbar. The configurational coordinate diagram gave a theoretical explanation for the Eu2+/3+result. The coated samples showed excellent moisture resistance while retaining an external quantum efficiency (EQE) of 70 % of their initial EQE after aging for 5 days under harsh conditions. White-light-emitting diodes of the SLA red phosphor and a commercial Y3Al5O12:Ce3+yellow phosphor on a blue InGaN chip showed high color rendition (CRI=89, R9=69) and a low correlated color temperature of 2406 K. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Subjects
charge transfer; coatings; light-emitting diodes; luminescence; phosphors
Other Subjects
Cerium alloys; Charge transfer; Coatings; Gallium alloys; III-V semiconductors; Indium alloys; Light; Light emitting diodes; Luminescence; Semiconductor alloys; Silica; Solid state reactions; Yttrium aluminum garnet; Correlated color temperature; External quantum efficiency; High isostatic pressure; High-pressure solids; Luminescence spectrum; Moisture resistance; White light emitting diodes; Zero phonon lines; Phosphors
Type
journal article