Porous silicon-zinc sulfide nanocomposite(PS-ZnS) was prepared by in situ synthesis of ZnS via a simple polyphase reaction on the base of nano-PS. The formation of the composite was confirmed by X-ray diffraction(XRD)...Porous silicon-zinc sulfide nanocomposite(PS-ZnS) was prepared by in situ synthesis of ZnS via a simple polyphase reaction on the base of nano-PS. The formation of the composite was confirmed by X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), energy dispersive spectroscopy(EDS) and photoluminescence(PL) measurements. Based on the XRD data and the Debye-Scherrer equation, the size of the formed ZnS particles both on the surface and in the holes of the PS was calculated to be nano-scaled, ca. 5—7 nm. FE-SEM observation showed agglomeration for the ZnS particles with an average crystallite size of 30—40 nm, and the hole diameter of the PS was below 100 nm. PL measurements and CIE diagram analysis for the PS-ZnS composite samples indicated that the emitted light color from the composites could be modulated and controlled by changing the annealing conditions, from orange to violet-blue, and finally, white-light emitter of the composite was obtained.展开更多
Powder phosphor of Sr2CeO4 is prepared by microemulsion-heating method and a film of the phosphor on ITO glass is formed by electrophoretic deposition. Field emission scanning electron microscopy （FE-SEM） images sho...Powder phosphor of Sr2CeO4 is prepared by microemulsion-heating method and a film of the phosphor on ITO glass is formed by electrophoretic deposition. Field emission scanning electron microscopy （FE-SEM） images show that the powder fired at 850 ℃ for 4 h has a spherical shape with an average diameter of 70 - 80 nm whereas the powder sintered at 900 ℃ for 4 h and 1000 ℃ for 4 h have shuttle-like and spherical shapes, respectively, with both sizes less than 1μm. X-ray diffraction （XRD） pattems indicate that the superfine Sr2CeO4 exhibits an orthorhombic crystal structure. Roomtemperature photoluminescence （PL） measurements show that there are three excitation peaks located at around 262, 280 and 341 nm, and all the Sr2CeO4 samples display an intense blue emission at 470 nm with CIE coordinate of （x, y） = （0.176, 0.283）. The quantum yield of phosphor is high up to 0.47 ±0.04. Compared with Sr2CeO4 samples prepared with traditional high-temperature heating, the phosphor synthesized with this method has a smaller size, lower calcination temperature, and shorter calcination time, and the main excitation and emission bands are blue shifted about 30 and 12 tun respectively. The startup voltage for Sr2CeO4 film on ITO glass shifts from 2700 to 4000 V with increasing thickness of the film.展开更多
文摘Porous silicon-zinc sulfide nanocomposite(PS-ZnS) was prepared by in situ synthesis of ZnS via a simple polyphase reaction on the base of nano-PS. The formation of the composite was confirmed by X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), energy dispersive spectroscopy(EDS) and photoluminescence(PL) measurements. Based on the XRD data and the Debye-Scherrer equation, the size of the formed ZnS particles both on the surface and in the holes of the PS was calculated to be nano-scaled, ca. 5—7 nm. FE-SEM observation showed agglomeration for the ZnS particles with an average crystallite size of 30—40 nm, and the hole diameter of the PS was below 100 nm. PL measurements and CIE diagram analysis for the PS-ZnS composite samples indicated that the emitted light color from the composites could be modulated and controlled by changing the annealing conditions, from orange to violet-blue, and finally, white-light emitter of the composite was obtained.
文摘Powder phosphor of Sr2CeO4 is prepared by microemulsion-heating method and a film of the phosphor on ITO glass is formed by electrophoretic deposition. Field emission scanning electron microscopy （FE-SEM） images show that the powder fired at 850 ℃ for 4 h has a spherical shape with an average diameter of 70 - 80 nm whereas the powder sintered at 900 ℃ for 4 h and 1000 ℃ for 4 h have shuttle-like and spherical shapes, respectively, with both sizes less than 1μm. X-ray diffraction （XRD） pattems indicate that the superfine Sr2CeO4 exhibits an orthorhombic crystal structure. Roomtemperature photoluminescence （PL） measurements show that there are three excitation peaks located at around 262, 280 and 341 nm, and all the Sr2CeO4 samples display an intense blue emission at 470 nm with CIE coordinate of （x, y） = （0.176, 0.283）. The quantum yield of phosphor is high up to 0.47 ±0.04. Compared with Sr2CeO4 samples prepared with traditional high-temperature heating, the phosphor synthesized with this method has a smaller size, lower calcination temperature, and shorter calcination time, and the main excitation and emission bands are blue shifted about 30 and 12 tun respectively. The startup voltage for Sr2CeO4 film on ITO glass shifts from 2700 to 4000 V with increasing thickness of the film.
