A distinct red-shift to 660 nm-featured longer wavelength of europium doped calcium sulphide nanocrystals was observed in a microwave （MW）-assisted solvothermal synthesis procedure. This red-shift was probably due t...A distinct red-shift to 660 nm-featured longer wavelength of europium doped calcium sulphide nanocrystals was observed in a microwave （MW）-assisted solvothermal synthesis procedure. This red-shift was probably due to a combined effect from Mg^2＋ codoping and strain accumulation at grain boundaries. The latter originated from the formation of small grains with an average size of around 200 nm in micrometer sized crystals upon Mg^2＋ codoping. In particular, MW electromagnetic field suppressed grain growth and enabled a reconstruction of atoms at the inner grain boundary at which the field strength was intensified around rare earth ions in host lattices. This MW synthesis route provided an option to prepare luminescent crystals with the desired blue-excitable longer wavelength emission.展开更多
This is the first report of using the microwave heating technique to synthesize calcium sulphide activated by europium whose structure is determined as the face-centered cubic by conventional X-ray powder diffraction ...This is the first report of using the microwave heating technique to synthesize calcium sulphide activated by europium whose structure is determined as the face-centered cubic by conventional X-ray powder diffraction method. The phosphor has maximum excitation peaks located at 280 urn and 560 urn and the maximum emission of the phosphor is 630 nm. When the concentration of Eu^(2+) in CaS increases from I .0 × 10^(-5) to l.0 × 10^(-2) mole per mole host, the body colour of the calcium sulphide activated with europium changes from white, through light-red to pink to deep-red. The phosphor obtains the longest afterglow at the concentration of 0.1% Eu^(2+)doped and is a kind of good material excited by sunlight.展开更多
基金supported by the National Natural Science Foundation of China(21076161)
文摘A distinct red-shift to 660 nm-featured longer wavelength of europium doped calcium sulphide nanocrystals was observed in a microwave （MW）-assisted solvothermal synthesis procedure. This red-shift was probably due to a combined effect from Mg^2＋ codoping and strain accumulation at grain boundaries. The latter originated from the formation of small grains with an average size of around 200 nm in micrometer sized crystals upon Mg^2＋ codoping. In particular, MW electromagnetic field suppressed grain growth and enabled a reconstruction of atoms at the inner grain boundary at which the field strength was intensified around rare earth ions in host lattices. This MW synthesis route provided an option to prepare luminescent crystals with the desired blue-excitable longer wavelength emission.
基金This work was supported by the National NatUral Science Foundation of China! (No 59982003) Guangdong Provincial NatUral Scie
文摘This is the first report of using the microwave heating technique to synthesize calcium sulphide activated by europium whose structure is determined as the face-centered cubic by conventional X-ray powder diffraction method. The phosphor has maximum excitation peaks located at 280 urn and 560 urn and the maximum emission of the phosphor is 630 nm. When the concentration of Eu^(2+) in CaS increases from I .0 × 10^(-5) to l.0 × 10^(-2) mole per mole host, the body colour of the calcium sulphide activated with europium changes from white, through light-red to pink to deep-red. The phosphor obtains the longest afterglow at the concentration of 0.1% Eu^(2+)doped and is a kind of good material excited by sunlight.
