Compounds of Sr3Al2O6 ： Eu, SrgAl14O25 ： Eu, and BaZnSiO4 ： Eu were synthesized by high-temperature solid state reactions. The doping Eu^3 ＋ ions were partially reduced to Eu^2＋ in Sr4Al14O25：Eu and BaZnSiOg：Eu...Compounds of Sr3Al2O6 ： Eu, SrgAl14O25 ： Eu, and BaZnSiO4 ： Eu were synthesized by high-temperature solid state reactions. The doping Eu^3 ＋ ions were partially reduced to Eu^2＋ in Sr4Al14O25：Eu and BaZnSiOg：Eu prepared in an oxidizing atmosphere, N^2 ＋ O2. However, such an abnormal reduction process could not be performed in Sr3Al2O6：Eu, which was also prepared in an atmosphere of N^2 ＋ O2. Moreover, even though Sr3A1EO6：Eu was synthesized in a reducing condition CO, only part of the Eu^3 ＋ ions was reduced to Eu^2 ＋ . The existence of trivalent and divalent europium ions was confirmed by photoluminescent spectra. The different valence-change behaviors of europium ions in the hosts were attributed to the difference in host crystal structures. The higher the crystal structure stiffness, the easier the reduction process from Eu^3 ＋ to Eu^2 ＋ .展开更多
Eu-doped silicate complex gel nano-particles was obtained by sol-gel process and characterized with TEM, XRD, PL, etc. The well dispersed particles have particle size about 60 - 70 nm with specific surface area 98.3 m...Eu-doped silicate complex gel nano-particles was obtained by sol-gel process and characterized with TEM, XRD, PL, etc. The well dispersed particles have particle size about 60 - 70 nm with specific surface area 98.3 m^2· g^- 1 The complex gel phosphor gives a broad and strong luminescent emission originating from Eu^2＋ ions centered at 425 nm. The emission band shifts to shorter wavelengths with the increase of the ion radius of the alkali earth metals, but the band becomes red-shifted gradually with the increase of the ion radius of the alkali metals（except Li ^＋ ）. These divalent Eu^2＋ ions originate in inequivalent substitution of the alkaline earth ions. The presence of alkaline ions is favorable for the increasing emission intensity of the Eu^2 ＋ and lowering crystalline temperature of the silicate complex gel.展开更多
基金Project supported bythe National Natural Science Foundation of China (50125258 ,60377040)
文摘Compounds of Sr3Al2O6 ： Eu, SrgAl14O25 ： Eu, and BaZnSiO4 ： Eu were synthesized by high-temperature solid state reactions. The doping Eu^3 ＋ ions were partially reduced to Eu^2＋ in Sr4Al14O25：Eu and BaZnSiOg：Eu prepared in an oxidizing atmosphere, N^2 ＋ O2. However, such an abnormal reduction process could not be performed in Sr3Al2O6：Eu, which was also prepared in an atmosphere of N^2 ＋ O2. Moreover, even though Sr3A1EO6：Eu was synthesized in a reducing condition CO, only part of the Eu^3 ＋ ions was reduced to Eu^2 ＋ . The existence of trivalent and divalent europium ions was confirmed by photoluminescent spectra. The different valence-change behaviors of europium ions in the hosts were attributed to the difference in host crystal structures. The higher the crystal structure stiffness, the easier the reduction process from Eu^3 ＋ to Eu^2 ＋ .
文摘Eu-doped silicate complex gel nano-particles was obtained by sol-gel process and characterized with TEM, XRD, PL, etc. The well dispersed particles have particle size about 60 - 70 nm with specific surface area 98.3 m^2· g^- 1 The complex gel phosphor gives a broad and strong luminescent emission originating from Eu^2＋ ions centered at 425 nm. The emission band shifts to shorter wavelengths with the increase of the ion radius of the alkali earth metals, but the band becomes red-shifted gradually with the increase of the ion radius of the alkali metals（except Li ^＋ ）. These divalent Eu^2＋ ions originate in inequivalent substitution of the alkaline earth ions. The presence of alkaline ions is favorable for the increasing emission intensity of the Eu^2 ＋ and lowering crystalline temperature of the silicate complex gel.
