The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The resu...The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The results show that the broad emission peaks at 430 nm correspond to 5d→4f emission transition of Eu2+, the sharp emission peaks at 592, 616, 650 and 750 nm correspond to 5D0→7Fj（j=1-4） emission transition of Eu3+, respectively, which indicates that the BaO-La2O3-B2O3-Eu2O3 glass can convert ultraviolet and green components of sunlight into blue and red light so as to increase the intensity of blue and red light, respectively. The luminescent intensity of Eu2+ increases with increasing the molar ratio of Tb3+ in BaO-La2O3-B2O3-Eu2O3-Tb4O7 glasses, whereas the luminescent intensity of Eu3+ decreases. So the luminescent intensity of Eu（III, II） is influenced by Tb3+. These phenomena can be explained by electron transfer mechanism: Eu3+（4f6）+Tb3+（4f8）→Eu2+（4f7）+Tb4+（4f7）. Taking advantage of the luminescent properties of BaO-La2O3-B2O3-Eu2O3 glasses, light-conversion glass for agriculture can be produced.展开更多
The microstructure, dielectric properties and chemical state of Ti element on BaTi_4O_9 (f)/(0.64 BaTi_4O_9-0.36BaPr_2Ti_4O_(12)) composites sample surface were characterized by X-ray diffraction (XRD), Transmission e...The microstructure, dielectric properties and chemical state of Ti element on BaTi_4O_9 (f)/(0.64 BaTi_4O_9-0.36BaPr_2Ti_4O_(12)) composites sample surface were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), LCR meter method and X-ray photoelectron spectroscopy (XPS). The results show that the system is composed of BaTi_4O_9 and BaPr_2Ti_4O_(12) two phases. Pr ions are distributed in the BaWi_4O_9 grains and the segregation of Pr ions was observed on the grain boundaries of BaTi_4O_9/BaTi_4O_9. The content of Ti^(3+) and Ti^(2+) decrease in the BPT system composites due to the addition of BaTi_4O_9 fibers, which improved the dielectric properties of the system. BPT10 sample with 10% BaTi_4O_9 fibers, has the best dielectric properties in the system, its ε_r = 64, tan δ= 1×10^(-4)(at 1 MHz) , and it may be a potential candidate for microwave dielectric ceramics.展开更多
文摘The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The results show that the broad emission peaks at 430 nm correspond to 5d→4f emission transition of Eu2+, the sharp emission peaks at 592, 616, 650 and 750 nm correspond to 5D0→7Fj（j=1-4） emission transition of Eu3+, respectively, which indicates that the BaO-La2O3-B2O3-Eu2O3 glass can convert ultraviolet and green components of sunlight into blue and red light so as to increase the intensity of blue and red light, respectively. The luminescent intensity of Eu2+ increases with increasing the molar ratio of Tb3+ in BaO-La2O3-B2O3-Eu2O3-Tb4O7 glasses, whereas the luminescent intensity of Eu3+ decreases. So the luminescent intensity of Eu（III, II） is influenced by Tb3+. These phenomena can be explained by electron transfer mechanism: Eu3+（4f6）+Tb3+（4f8）→Eu2+（4f7）+Tb4+（4f7）. Taking advantage of the luminescent properties of BaO-La2O3-B2O3-Eu2O3 glasses, light-conversion glass for agriculture can be produced.
文摘The microstructure, dielectric properties and chemical state of Ti element on BaTi_4O_9 (f)/(0.64 BaTi_4O_9-0.36BaPr_2Ti_4O_(12)) composites sample surface were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), LCR meter method and X-ray photoelectron spectroscopy (XPS). The results show that the system is composed of BaTi_4O_9 and BaPr_2Ti_4O_(12) two phases. Pr ions are distributed in the BaWi_4O_9 grains and the segregation of Pr ions was observed on the grain boundaries of BaTi_4O_9/BaTi_4O_9. The content of Ti^(3+) and Ti^(2+) decrease in the BPT system composites due to the addition of BaTi_4O_9 fibers, which improved the dielectric properties of the system. BPT10 sample with 10% BaTi_4O_9 fibers, has the best dielectric properties in the system, its ε_r = 64, tan δ= 1×10^(-4)(at 1 MHz) , and it may be a potential candidate for microwave dielectric ceramics.
