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

Abstract

A SrLiAl3 N4 :Eu(2+) (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 4f(6) 5d→4f(7) transition bands are thought to result from the existence of Eu(2+) at two different Sr(2+) 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 Eu(2+/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 Y3 Al5 O12 :Ce(3+) yellow phosphor on a blue InGaN chip showed high color rendition (CRI=89, R9=69) and a low correlated color temperature of 2406 K.

Controlling of Structural Ordering and Rigidity of β-SiAlON:Eu through Chemical Cosubstitution to Approach Narrow-Band-Emission for Light-Emitting Diodes Application

“…. 41,42 When Al→Si and O→N substitutions simultaneously occur in β-Si3N4, a structure of β-SiAlON is obtained, similar to that of β-Si3N4. As z increases, such substitution would inevitably cause an increasing degree of structural disorder in the framework of β-Si3N4, and consequently result in a decrease in the force constant of the Si-N bond.…”

Sr[BeSi2N4]:Eu2+/Ce3+ and Eu[BeSi2N4]: Nontypical Luminescence in Highly Condensed Nitridoberyllosilicates

“…Therefore we assess insoluble, coarse‐grained Be‐containing solid‐state compounds with a large density to be less dangerous and handling with appropriate safety measures is feasible. In principle, application of beryllate phosphors in pcLEDs is conceivable, as same coatings for sensitive phosphors, for example, with silica, could protect from exposure and intoxication due to accidental incorporation …”

“…In principle, application of beryllate phosphors in pcLEDs is conceivable, as same coatings for sensitive phosphors, for example, with silica, could protect from exposure and intoxication due to accidental incorporation. [44] Synthesis Due to the starting materials' high sensitivity to moisture and air, and toxicity of Be dusts, experiments were performed in argonfilled glove boxes (Unilab, MBraun, Garching;O 2 < 1ppm, H 2 O < 1ppm) or in dry Schlenk-type glassware attached to av acuum line (10 À3 mbar). Purification of argon gas (Air Liquide, 5.0) was performed in columns filled with silica gel (Merck), molecular sieves (Fluka, 4 ), KOH (Merck, !…”

Oxoberyllates SrBeO2 and Sr12Be17O29 as Novel Host Materials for Eu2+ Luminescence

“…Therefore, we assess insoluble, coarse‐grained Be‐containing solid‐state compounds with large density to be less dangerous, and handling with appropriate safety measures, such as working in closed containers, for example, gloveboxes, is feasible. In principle, application of beryllate phosphors in pc‐LEDs is conceivable, as the same coatings for sensitive phosphors, for example, with silica, could protect from exposure and intoxication due to accidental incorporation …”