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Microstructure and Photoluminescence Characterizations of Y 3 Al 5 O 12 :Ce Phosphor Ceramics Sintered with Silica
Author(s) -
Nien YungTang,
Lu TzungHeng,
Rao Bandi Vengala,
Chen InGann
Publication year - 2012
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/j.1551-2916.2011.04986.x
Subject(s) - microstructure , materials science , sintering , phosphor , photoluminescence , scanning electron microscope , ceramic , analytical chemistry (journal) , fourier transform infrared spectroscopy , transmission electron microscopy , ionic radius , dopant , doping , sol gel , mineralogy , chemical engineering , composite material , nanotechnology , ion , chemistry , chromatography , optoelectronics , organic chemistry , engineering
The effects of silica additions (0.5–5 wt%) and sintering temperatures (980°C–1400°C) on the microstructure and photoluminescence ( PL ) of Ce ‐doped Y 3 Al 5 O 12 ( YAG:Ce ) phosphor ceramics were investigated in this study. Fourier transform infrared ( FTIR ) measurements showed the disappearance of silica (1 wt%) at 1200°C, indicating the incorporation of Si into YAG host and agreeing with the nuclear magnetic resonance ( NMR ) results. Microstructures of YAG:Ce ceramics with various silica additions observed using scanning electron microscope ( SEM ) and transmission electron microscope ( TEM ) revealed an obvious increasing densification and grain growth for the samples of >2.5 wt% silica at 1400°C. PL analysis demonstrated a higher intensity with increasing the sintering temperatures and the amount of silica addition. Two reasons were supposed to induce this PL enhancement of silica‐treated YAG:Ce ceramics. First, Si will replace tetrahedral Al sites and induce a homogeneous diffusion as well as distribution of Ce dopant in the YAG host due to a smaller ionic radius of Si (0.026 nm) than that of Al (0.039 nm). Secondly, a liquid phase sintering will occur with the presence of silica in YAG:Ce , resulting in the densification of ceramics and an easier migration of Ce activators to inhibit the concentration quenching effect.