Increases of emission intensities for Eu 3+ at the S 6 site relative to that at the C 2 site were observed as UV excitation wavelength decreases from 300 nm to 200 nm in both bulk and nanocrystalline cubic Y 2O 3...Increases of emission intensities for Eu 3+ at the S 6 site relative to that at the C 2 site were observed as UV excitation wavelength decreases from 300 nm to 200 nm in both bulk and nanocrystalline cubic Y 2O 3:Eu 3+. Decomposition of excitation spectra shows that the charge transfer band of Eu 3+ at the S 6 site lies in the high-energy side of that at the C 2 site, resulting in that the energy transfer from the host prefers to the S 6 site. Detailed emission and excitation spectral characteristics were analyzed and discussed. In addition, spectral red-shift were found in both charge transfer bands in nanocrystalline Y 2O 3:Eu 3+ compared to the bulk material. The number ratio of S 6 sites to C 2 sites is also smaller in nanocrystalline Y 2O 3:Eu 3+ than that in the bulk one.展开更多
以荧光强度为指标,采用L9(3^4)正交实验优化纳米荧光粉YPO4:2%Sm^3+的水热工艺条件(反应温度、反应时间、溶液的阴/阳离子比和pH值)。用X射线衍射仪(XRD)、扫描电镜及能谱(SEM and EDS)、荧光分光光度计(FL)、红外光谱仪(FT-IR)和紫外...以荧光强度为指标,采用L9(3^4)正交实验优化纳米荧光粉YPO4:2%Sm^3+的水热工艺条件(反应温度、反应时间、溶液的阴/阳离子比和pH值)。用X射线衍射仪(XRD)、扫描电镜及能谱(SEM and EDS)、荧光分光光度计(FL)、红外光谱仪(FT-IR)和紫外光谱仪(UV)等仪器对样品的组成、结构、形貌及其发光性能进行了表征和分析。结果表明,影响纳米荧光粉YPO4:2%Sm^3+水热工艺条件的主次因素为反应温度>pH值>反应时间>阴/阳离子比。最佳的水热工艺条件为反应温度为200℃、pH=3、反应时间为12 h、阴/阳离子比3:1。最佳纳米荧光粉的结构为单一的四方晶体结构,形貌为纳米球,荧光强度最大,荧光寿命为0.1719ms,禁带宽度为5.14 eV,色坐标为X=0.556 3, Y=0.433 9。展开更多
文摘Increases of emission intensities for Eu 3+ at the S 6 site relative to that at the C 2 site were observed as UV excitation wavelength decreases from 300 nm to 200 nm in both bulk and nanocrystalline cubic Y 2O 3:Eu 3+. Decomposition of excitation spectra shows that the charge transfer band of Eu 3+ at the S 6 site lies in the high-energy side of that at the C 2 site, resulting in that the energy transfer from the host prefers to the S 6 site. Detailed emission and excitation spectral characteristics were analyzed and discussed. In addition, spectral red-shift were found in both charge transfer bands in nanocrystalline Y 2O 3:Eu 3+ compared to the bulk material. The number ratio of S 6 sites to C 2 sites is also smaller in nanocrystalline Y 2O 3:Eu 3+ than that in the bulk one.
