Open AccessMn4+activated Al2O3red-emitting ceramic phosphor with excellent thermal conductivity
Author(s) -
Cuicui Tian,
Hui Lin,
Dawei Zhang,
Peiping Zhang,
Richang Hong,
Zhaoxia Han,
Xinglu Qian,
Jun Zou
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.032666
Subject(s) - phosphor , materials science , luminescence , ceramic , analytical chemistry (journal) , excited state , crystal (programming language) , thermal conductivity , quantum efficiency , ion , optoelectronics , atomic physics , chemistry , physics , composite material , organic chemistry , chromatography , computer science , programming language
An Al 2 O 3 :Mn 4+ , Mg 2+ red emitting ceramic phosphor, which can be effectively excited by ultraviolet and blue light, was successfully synthesized via solid-state reaction in an oxygen and air atmosphere. The ceramic sintered in oxygen atmosphere has higher optical transmittance and stronger luminescence intensity than the ceramic sintered in the air, which is more suitable for LED application. Since the structure of α-Al 2 O 3 is very simple, it is convenient to study the factors affecting the Mn 4+ luminescence. The crystal-strength parameter Dq, Racah parameters B and C, and the nephelauxetic ratio β 1 were calculated to investigate the influence of crystal field strength and nephelauxetic effect on the emission of Mn 4+ in the Al 2 O 3 host. The ratio of Dq to B was 1.74, which was lower than 2.2. This indicated that the Mn 4+ ions in the α-Al 2 O 3 host were in a weak crystal field environment. Under the 395 nm and 460 nm excitations, quantum yields (QY) of the sample were measured to be 46% and 28.7%, respectively. The density measured by the Archimedes method was 3.61 g/cm 3 . The ceramic also showed an excellent thermal conductivity value, which was as high as 26.27 W·m -1 ·K -1 @30 °C.