The photoluminescence of Dy^(3+) doped and Dy^(3+), Ce^(3+) codoped in Ba_3La(BO_3)_3 were studied. The dependence of the charge-to-radius ratio (z/r) for RE^(3+)(RE=La, Ce), the Ce^(3+), Dy^(3+) content on the emissi...The photoluminescence of Dy^(3+) doped and Dy^(3+), Ce^(3+) codoped in Ba_3La(BO_3)_3 were studied. The dependence of the charge-to-radius ratio (z/r) for RE^(3+)(RE=La, Ce), the Ce^(3+), Dy^(3+) content on the emission intensity and the yellow to blue intensity ratio (Y/B) of Dy^(3+) were investigated too. The results obtained indicate that Ce^(3+) can sensitize the luminescence of Dy^(3+). The optimum concentration of Dy^(3+) in Ba_3La(BO_3)_3 is x_(Dy)=0.06. According to the dependence of the concentration of Dy^(3+) in Ba_3La(BO_3)_3 under the excitation of 350 nm, it is confirmed that the mechanism of concentration selfquenching of Dy^(3+) () (()~4F_(9/2)→()~6H_(15/2),) (()~6H_(13/2)) transition is electric dipole-quadrupole interaction.展开更多
Europium (Eu￣(3+)) doped polycrystalline (LaO)_3BO_3 has been synthesized by solid state reaction with Li_2CO_3 as flux at 1200℃ for 10 h in air. X- ray powder diffraction shows that ( LaO)_3BO_3 crystallizes in a...Europium (Eu￣(3+)) doped polycrystalline (LaO)_3BO_3 has been synthesized by solid state reaction with Li_2CO_3 as flux at 1200℃ for 10 h in air. X- ray powder diffraction shows that ( LaO)_3BO_3 crystallizes in a monoclinic cell [a= 0. 69214 (9)nm , b=1. 2929(3) nm , c=1. 4590 (3 ) nm . β= 99. 35 (2)°,V= 1. 2882(4 ) nm￣3 and Z= 8] with a possible space group of P2_1/m or P2_1. The predominance of electric-dipole transition ￣5D_0→ ￣7F_2 in the fluorescence spectrum , as well as the splitting of the￣7F_j ground states of Eu￣(3+) reveals that the lanthanum atoms distribute in the sites with C_1 or C_s symmetry in this structure.展开更多
采用传统固相法制备了(Ba_(0.9)Ca_(0.1))_(1–x)La_x(Ti_(0.8)Zr_(0.2))O_3(0≤x≤0.005)系列无铅陶瓷,并研究了微量La取代对锆钛酸钡钙陶瓷微观结构及介电性能的影响。X射线衍射和扫描电镜结果表明,La^(3+)进入锆钛酸钡钙晶格中形成...采用传统固相法制备了(Ba_(0.9)Ca_(0.1))_(1–x)La_x(Ti_(0.8)Zr_(0.2))O_3(0≤x≤0.005)系列无铅陶瓷,并研究了微量La取代对锆钛酸钡钙陶瓷微观结构及介电性能的影响。X射线衍射和扫描电镜结果表明,La^(3+)进入锆钛酸钡钙晶格中形成均一的固溶体,并能有效抑制陶瓷颗粒的增长。介电性能测试结果显示,随着La^(3+)含量的增加,居里温度降低,室温介电常数先增大后减小,介电损耗则相反的趋势,取代后的样品介电频率稳定性增强。样品(Ba_(0.9)Ca_(0.1))_(0.997)La_(0.003)(Ti_(0.8)Zr_(0.2))O_3的综合介电性能最佳,在频率为1 k Hz时,室温介电常数可达18 592,而相应的介电损耗仅为0.013,居里温度为281 K。展开更多
文摘The photoluminescence of Dy^(3+) doped and Dy^(3+), Ce^(3+) codoped in Ba_3La(BO_3)_3 were studied. The dependence of the charge-to-radius ratio (z/r) for RE^(3+)(RE=La, Ce), the Ce^(3+), Dy^(3+) content on the emission intensity and the yellow to blue intensity ratio (Y/B) of Dy^(3+) were investigated too. The results obtained indicate that Ce^(3+) can sensitize the luminescence of Dy^(3+). The optimum concentration of Dy^(3+) in Ba_3La(BO_3)_3 is x_(Dy)=0.06. According to the dependence of the concentration of Dy^(3+) in Ba_3La(BO_3)_3 under the excitation of 350 nm, it is confirmed that the mechanism of concentration selfquenching of Dy^(3+) () (()~4F_(9/2)→()~6H_(15/2),) (()~6H_(13/2)) transition is electric dipole-quadrupole interaction.
文摘Europium (Eu￣(3+)) doped polycrystalline (LaO)_3BO_3 has been synthesized by solid state reaction with Li_2CO_3 as flux at 1200℃ for 10 h in air. X- ray powder diffraction shows that ( LaO)_3BO_3 crystallizes in a monoclinic cell [a= 0. 69214 (9)nm , b=1. 2929(3) nm , c=1. 4590 (3 ) nm . β= 99. 35 (2)°,V= 1. 2882(4 ) nm￣3 and Z= 8] with a possible space group of P2_1/m or P2_1. The predominance of electric-dipole transition ￣5D_0→ ￣7F_2 in the fluorescence spectrum , as well as the splitting of the￣7F_j ground states of Eu￣(3+) reveals that the lanthanum atoms distribute in the sites with C_1 or C_s symmetry in this structure.
文摘采用传统固相法制备了(Ba_(0.9)Ca_(0.1))_(1–x)La_x(Ti_(0.8)Zr_(0.2))O_3(0≤x≤0.005)系列无铅陶瓷,并研究了微量La取代对锆钛酸钡钙陶瓷微观结构及介电性能的影响。X射线衍射和扫描电镜结果表明,La^(3+)进入锆钛酸钡钙晶格中形成均一的固溶体,并能有效抑制陶瓷颗粒的增长。介电性能测试结果显示,随着La^(3+)含量的增加,居里温度降低,室温介电常数先增大后减小,介电损耗则相反的趋势,取代后的样品介电频率稳定性增强。样品(Ba_(0.9)Ca_(0.1))_(0.997)La_(0.003)(Ti_(0.8)Zr_(0.2))O_3的综合介电性能最佳,在频率为1 k Hz时,室温介电常数可达18 592,而相应的介电损耗仅为0.013,居里温度为281 K。
