Preparation and Characterization of Yttrium Oxysulfide and Yttrium Oxide Phosphors
Date Issued
2007
Date
2007
Author(s)
Liu, Fu-Wen
DOI
en-US
Abstract
Europium-ion doped yttrium oxysulfide (Y2O2S: Eu3+) is a promising phosphors for flat panel displays. Y2O2S: Eu3+ phosphors were synthesized via a solid state reaction with different fluxes and sources of sulfur. The crystal structure, surface morphology, and photoluminescent properties were investigated. Y2O2S: Eu3+ phosphors were also prepared via a new facile gel-coating route using thiourea as a source of sulfur without adding fluxes. Y2O2S: Eu3+ phosphors with a pure hexagonal structure were obtained after calcination at elevated temperatures. The morphology of Y2O2S: Eu3+ phosphors was irregular shaped particles with the size of 10 µm. The structural orientations were found to be varied with different calcination temperatures. The varied orientations were evidenced from the intensity ratio of diffraction peaks. The red emission of Y2O2S: Eu3+ phosphors was attributed to the transitions from 5D0 to 7FJ (J = 0, 1, and 2) of Eu3+. The photoluminescent intensity of the Y2O2S: Eu3+ phosphors was found to be a function of calcination temperature and crystallographic orientation.
Europium-ion doped yttrium oxide phosphors were synthesized via a rapid microwave-assisted solvothermal route. The microwave processing time for synthesizing precursors of Y2O3: Eu3+ powders was as short as 5 min. The as-synthesized precipitates exhibited an amorphous phase, and well-crystallized pure phase of Y2O3: Eu3+ powders were formed after further calcination. The morphology of the precipitated powders was spherical, and the spherical
particles were composed of small nanograins. The synthesized powders retained the spherical morphology after heating treatments. An intense red emission at 611 nm was assigned to a 5D0-7F1 transition of Eu3+. Both photoluminescent intensity and crystallite size significantly increased with increasing calcination temperatures. The microwave-assisted solvothermal method could be applied to prepare other spherical phosphors.
Subjects
硫氧化釔
氧化釔
微波溶熱
凝膠塗佈
螢光粉
Yttrium Oxysulfide
Yttrium Oxide
microwave solvothermal
gel-coating
phosphor
Type
thesis