Color-tunable phosphors Sr0.94MoO4：xEu^3＋, （0.06 - x）Tb^3＋ were synthesized rapidly by microwave ra- diation method with active carbon particle as microwave absorbent. The synthesized phosphors were investigated ...Color-tunable phosphors Sr0.94MoO4：xEu^3＋, （0.06 - x）Tb^3＋ were synthesized rapidly by microwave ra- diation method with active carbon particle as microwave absorbent. The synthesized phosphors were investigated by X-ray powder diffraction （XRD） and fluorescence spec- trophotometer. The effects of the ratio of Eu^3＋ and Tb^3＋ on the phase structure and luminescent properties of the phos- phors were discussed. The results show that Eu^3＋,Tb^3＋-doped samples can be well indexed to the pure tetragonal scheelite- type SrMoO4, indicating that Eu^3＋ and Tb^3＋ are effectively doped into the SrMoO4 host lattices. The as-synthesized Sro.94MoO4：xEu^3＋,（0.06 - x）Tb^3＋ phosphors have two luminescent centers （Eu^3＋ and Tb^3＋）, which can show red and green emissions under ultraviolet light excitation, respec- tively. Doping concentration of Eu^3＋ and Tb^3＋ has great effect on the intensity of emission peaks and the chromaticity of the samples, and the full color between green and red light can be achieved by adjusting the relative concentration of Eu^3＋ and Tb^3＋.展开更多
Well-dispersed uniform SrMoO4 nanocrystals were synthesized by thermal decomposition of a metalorganic salt in the organic solvent under different temperatures（80, 100, 120, 140, and 160？C）. The smallest diameter o...Well-dispersed uniform SrMoO4 nanocrystals were synthesized by thermal decomposition of a metalorganic salt in the organic solvent under different temperatures（80, 100, 120, 140, and 160？C）. The smallest diameter of these SrMoO4 nanocrystals is only about 2 nm, which is regarded as the smallest values to date. The UV–vis absorbance spectra present that the larger absorption of our samples is mainly distributed in the visible light region and UV light region. The lowest energy gap is found to be 2.71 e V.Such a small gap is ascribed to the introduction of intermediate energy levels, which are due to the surface defects with decreasing the size of nanostrcutrues. The photoluminescence measurement suggests that all these samples exhibit a board and strong emission band in the range from 500 to 700 nm. Through the deconvolution of the photoluminescence spectra, the emission profiles are found to be associated with three various components（green, yellow, and red）. Moreover, the photodegration of methyl blue over our SrMoO4 samples reaches nearly 100% in 120 min. Such a high photodegration may be related to the following aspects. One is related to the size and morphology. Larger surface area leads to more absorption of methyl blue, and the small size nanoparticles lead to the efficient separation of these photogenerated electron-hole pairs. The other is related to the narrow band gap. The small gap is beneficial to more electrons to be excited from the valence band to the conduction band, and eventually more electron-hole pairs are created. Our investigations clearly suggest that thermal decomposition of one metal-organic salt in organic solvent will be a good choice to synthesize the nanoparticles with small size and uniform distribution. Our results also indicate that these SrMoO4 nanoparticles possibly have great potential utilities in photocatalysts.展开更多
基金financially supported by the National Natural Science Foundation of China (No.21301046)
文摘Color-tunable phosphors Sr0.94MoO4：xEu^3＋, （0.06 - x）Tb^3＋ were synthesized rapidly by microwave ra- diation method with active carbon particle as microwave absorbent. The synthesized phosphors were investigated by X-ray powder diffraction （XRD） and fluorescence spec- trophotometer. The effects of the ratio of Eu^3＋ and Tb^3＋ on the phase structure and luminescent properties of the phos- phors were discussed. The results show that Eu^3＋,Tb^3＋-doped samples can be well indexed to the pure tetragonal scheelite- type SrMoO4, indicating that Eu^3＋ and Tb^3＋ are effectively doped into the SrMoO4 host lattices. The as-synthesized Sro.94MoO4：xEu^3＋,（0.06 - x）Tb^3＋ phosphors have two luminescent centers （Eu^3＋ and Tb^3＋）, which can show red and green emissions under ultraviolet light excitation, respec- tively. Doping concentration of Eu^3＋ and Tb^3＋ has great effect on the intensity of emission peaks and the chromaticity of the samples, and the full color between green and red light can be achieved by adjusting the relative concentration of Eu^3＋ and Tb^3＋.
基金supported by the National Science Foundation of China(Nos.11204001 and 51471001)supported by the Anhui University Scientific Research Fund(No.201610357120)the Collaborative Innovation Research Center for Weak Signal Sensitive Materials and Devices Integration
文摘Well-dispersed uniform SrMoO4 nanocrystals were synthesized by thermal decomposition of a metalorganic salt in the organic solvent under different temperatures（80, 100, 120, 140, and 160？C）. The smallest diameter of these SrMoO4 nanocrystals is only about 2 nm, which is regarded as the smallest values to date. The UV–vis absorbance spectra present that the larger absorption of our samples is mainly distributed in the visible light region and UV light region. The lowest energy gap is found to be 2.71 e V.Such a small gap is ascribed to the introduction of intermediate energy levels, which are due to the surface defects with decreasing the size of nanostrcutrues. The photoluminescence measurement suggests that all these samples exhibit a board and strong emission band in the range from 500 to 700 nm. Through the deconvolution of the photoluminescence spectra, the emission profiles are found to be associated with three various components（green, yellow, and red）. Moreover, the photodegration of methyl blue over our SrMoO4 samples reaches nearly 100% in 120 min. Such a high photodegration may be related to the following aspects. One is related to the size and morphology. Larger surface area leads to more absorption of methyl blue, and the small size nanoparticles lead to the efficient separation of these photogenerated electron-hole pairs. The other is related to the narrow band gap. The small gap is beneficial to more electrons to be excited from the valence band to the conduction band, and eventually more electron-hole pairs are created. Our investigations clearly suggest that thermal decomposition of one metal-organic salt in organic solvent will be a good choice to synthesize the nanoparticles with small size and uniform distribution. Our results also indicate that these SrMoO4 nanoparticles possibly have great potential utilities in photocatalysts.
