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Enhanced thermal stability of CaAlSiN 3 :Eu 2+ phosphors by superficial carbon modification
Author(s) -
Tian Junhang,
Zhuang Weidong,
Liu Ronghui,
Liu Yuanhong,
Chen Guantong,
Jiang Ze,
Zhang Xia,
Gao Wei,
Li Wenjin
Publication year - 2020
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17423
Subject(s) - phosphor , raman spectroscopy , thermal stability , materials science , luminescence , carbon fibers , surface modification , x ray photoelectron spectroscopy , chemical engineering , analytical chemistry (journal) , chemistry , composite material , optoelectronics , optics , organic chemistry , physics , composite number , engineering
To satisfy increasing stringent application requirements for high power wLEDs, we propose a superficial carbon modification method to enhance thermal stability of red‐emitting CaAlSiN 3 :Eu 2+ phosphor via carbon coating by mechanical mixing and thermal post‐treatment at high temperature under N 2 ‐H 2 atmosphere. The modifications on the crystal surface include (a) elimination of amorphous phase, (b) introduction of carbon and (c) inhibition of the oxidation of Eu 2+ . During the whole processing, the route of carbon and its effects on the crystal structure and luminescence properties are investigated by XPS, TEM, SEM, Raman spectra and TG‐DSC analysis. After superficial carbon modification, the thermal quenching characteristic is improved by 5.7%, and the relative brightness decays more slowly during the aging test, which means that the superficial carbon modified samples still maintain good luminescence performance at high temperature and have superior performance for long‐term applications. All above indicate that the superficial carbon modification method is a promising application to enhance the thermal stability for analogous Eu 2+ ‐activated nitride phosphors.