Journal
JOURNAL OF ALLOYS AND COMPOUNDS
Volume 843, Issue -, Pages -Publisher
ELSEVIER SCIENCE SA
DOI: 10.1016/j.jallcom.2020.154939
Keywords
BaAl2Si3O4N4; Two-steps process; Thermal stability; Enhanced photoluminescence
Categories
Funding
- National Natural Science Foundation of China [61875176]
- Zhejiang Provincial Natural Science Foundation of China [LZ20E020001, LY19F050009]
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A series of novel blue-emitting Ba1-xAl2Si3O4N4: xEu(2+) phosphors were successfully prepared by two-steps high temperature solid state reaction. The results of XRD and SEM showed that the two-steps method obtain less impurities than the traditional one-step method. The electronic band structure of BaAl2Si3O4N4 (BASON) host was calculated as a direct band gap of 3.662eV by the DFT method. The PLE spectrum of B(1-x)ASON: xEu(2+) showed a wide band excitation in the wavelength range of 250-450 nm, which can be well matched with n-UV chips. Based on crystal structural and fluorescence lifetime analysis, three emission peaks were obtained by gaussian fitting to explain the asymmetry of Eu2+ emission in the BASON phosphor. The optimal doping concentration of Eu2+ was x = 0.04. According to calculated critical distance (3.24 angstrom) and a little overlap between PLE and PL spectra, the concentration quenching mechanism was confirmed as both of dipole-dipole interaction and radiation reabsorption. In addition, with the incorporation of Eu2+, the diffuse reflection spectrum of B(1-x)ASON: xEu(2+) presented a wide absorption peak in the range of 200-500 nm. The PL intensity of Ba0.96-ySryAl2Si3O4N4: 0.04Eu(2+) tended to rise first and then fall with the increase of Sr2+ concentration. Impressively, the relative emission intensity at 473K still maintained 95.7% compared with room temperature (293K), which indicated the excellent thermal stability of BASON phosphor. Finally, the density of state (DOS) of Ba1-ySryAl2Si3O4N4 (y = 0, 0.5, 1) were calculated and analyzed to explain the deterioration of thermal stability with the increase of Sr2+ substitution. (C) 2020 Published by Elsevier B.V.
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