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961.
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963.
在外加强磁场条件下,采用溶胶-凝胶法制备了镍离子掺杂二氧化钛光催化剂,并进行紫外光下降解甲基橙溶液的实验,考查了磁感应强度对光催化剂催化活性的影响。借助XRD、EDS、SEM、IR及PL等手段对掺杂催化剂结构进行了表征。结果表明:外加强磁场使催化剂的粒径减小,颗粒分布均匀,利于镍离子掺杂进入二氧化钛内部,降低了催化剂的带隙能,同时又降低了电子空穴对复合率,提高了催化剂的电子-空穴对分离效率,增大了光催化活性,且随着磁感应强度的增加,催化剂的光催化活性逐渐增大。 相似文献
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966.
采用高温固相反应法合成了蓝色荧光粉NaBa0.98P04:Eu2+0.02.利用射线衍射(XRD)、扫描电镜(SEM)和荧光光谱等实验技术,研究了掺杂离子和掺杂浓度对荧光粉的晶体结构和发光性能的影响.结果表明:制备的粉末为单斜晶系NaBaP04,能被从紫外到蓝光波长范围的激发光有效激发,在波长360nm激发光激发下,发射光为波长在430nm左右的蓝光.同时,研究表明最佳掺杂离子为Ca2+,最佳掺杂浓度为7% mol,荧光粉NaBa0.91Ca0.07PO4:Eu2+0.02的发光强度是NaBa0.98PO4:Eu2+0.02的1.68倍,该方法制备的荧光粉是一种很好的白光LED的蓝色荧光粉材料. 相似文献
967.
FU Shaobo CHEN Baojiu LI Xiangping ZHANG Jinsu TIAN Yue SUN Jiashi ZHONG Haiyang CHENG Lihong WU Zhongli 《中国稀土学报(英文版)》2012,30(10):979-984
Eu3+-doped binary borate glasses with different metal oxide components RO (R=Ca, Sr, Ba, Zn or Pb) were prepared by meltquenching technique. The fluorescent spectral properties of Eu3+in these glasses were experimentally studied. The analysis on the phonon sidebands (PSBs) indicated that RO component did not cause obvious change of the electron-phonon coupling constant (EPC). By inspecting the optical absorption edges it was found that RO could greatly affect the band gap energy, and the glass with PbO component revealed the smallest band gap energy, the glasses with ZnO, BaO and SrO showed similar band gap energy. The optical transition intensity parameters of Eu3+in all studied glasses were calculated, it was found that for each sample its value of2 was larger than that of 4 and 6, and the sample with PbO component exhibited the smallest2, but the λ values for ZBE, CBE, BBE and SBE were very similar. These results might be helpful for the design of borate glasses. 相似文献
968.
A deep red-emitting SrB4O7:Sm2+ phosphor for light conversion agent was synthesized by the conventional solid-state reaction. X-ray powder diffraction (XRD) analysis confirmed the phase formation of SrB4O 7:Sm2+ materials. Results of luminescence properties showed that the phosphor could be efficiently excited by the UV-vis light region from 250-500 nm, and it exhibited deep red (685 nm) emission corresponding to 5D0 → 7F0 transition of Sm 2+ . The critical quenching concentration of Sm 2+ in SrB4O7 :Sm 2+ phosphor was about 0.05, and the corresponding concentration quenching mechanism was verified to be the dipole-dipole interaction according to the Dexter’s theory. The decay times had few alterations with different concentrations in SrB4O7:xSm 2+ phosphor. 相似文献
969.
A two colour phosphor Ba 2 Mg(BO3)2:Ce3+,Eu2+,Na+ was synthesized using solid-state reaction method.Luminescence of Ba2Mg(BO3)2:Ce3+,Eu2+,Na+ showed 416 and 618 nm emission bands attributed to Ce3+ and Eu2+ emission, respectively. Energy transfer occurred from Ce3+ to Eu2+ through a significant overlap of Eu 2+ excitation spectrum with Ce3+ emission spectrum in Ba 2 Mg(BO3)2. They also showed that under the excitation of UV radiation, bluish or yellowish white light was generated by coupling a broad blue emission band and a red emission band.By combining with green phosphor, Ba2Mg(BO3 ):Ce3+,Eu2+,Na+ phosphor showed potential application for white light-emitting diodes (LEDs). 相似文献
970.
Rare earth (La,Nd and Tb) oxides with one-dimensional micro/nanostructures were synthesized hydrothermally under facile and mild conditions with two surfactants, and characterized by X-ray diffraction (XRD), thermal gravimetry (TG), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence. The results showed that the synthesized rare earth oxides behaved regular nano-and micro-scale structures. And the morphologies of samples depended on the radii of rare earth ions, with the help of two surfactants of sodium dodecyl sulfonic and PEG 600. Nanocrystalline La2O3:Eu3+ possessed good photoluminescence (PL) property and might be used as a nanosized phosphor, its PL intensity was altered by the doping Eu3+ concentration and the optimum concentration of Eu3+ was 3 mol.%. In comparison with bulk Eu3+/La2O3, Eu3+/nano-La2O3 showed better photoluminescence property, nearly equal to that of nanocrtstal-line La2O3:Eu3+. Tb4O7 microwires showed interesting photoluminescence properties. 相似文献