【摘要】 用水热法合成了Tm³⁺/Er³⁺/Yb³⁺三掺杂YF₃上转换发光粉末,并对其进行了结构和形貌表征。对上转换发射谱的研究表明,在相对低激发功率下,可以观察到比较明亮的近白色发光,且随着激发功率的增大,上转换发射强度迅速增大并达到饱和状态,继续增大激发功率,出现发光猝灭现象。退火温度对上转换发射强度的影响表明,随着退火温度的升高,Tm³⁺,Er³⁺的所有特征发射峰均相对增强。上转换发射谱随Tm³⁺浓度变化关系表明,在相对低Tm³⁺掺杂浓度下,Tm³⁺-Er³⁺相互作用占优势,Tm³⁺把能量传递给Er³⁺,Er³⁺发射相对增强;在相对高掺杂浓度下,Tm³⁺-Tm³⁺之间交叉弛豫过程占优势,Er³⁺发射相对减弱。从实验结果看出,该粉末的上转换发光非常丰富,从紫外到红外均有发射,是一种潜在的白色上转换发光及三维固体显示材料。更多还原

【Abstract】 Tm³⁺/Er³⁺/Yb³⁺ tri-doped YF₃ powders were synthesized using a facile hydrothermal method. XRD analysis found that the powders were crystallized products.Their sizes and morphologies were character- ized by scanning electron micrographs （SEM,Hitachi S-4800）,which indicated that most of the YF₃ powders were in the sizes of hundreds of nanometers.Under 980 nm excitation,we recorded the upconversion spectra at room temperature by Hitachi F-4500.From UV to IR,plenty of upconversion emissions of Tm³⁺ and Er³⁺ were observed.For Tm³⁺,～291 nm emissions come from ¹I₆→³H₆,～347 nm from ¹I₆→³F₄,～362 nm from ¹D2→³H₆,～452 nm from ¹D₂→³F₄,and～475 nm from ¹G₄→³H₆ can be identified in the upconver- sion spectra.The upconversion emissions from Er³⁺ are:～380 nm (⁴G_11/2→⁴I_15/2),～408 nm(²H_9/2→⁴I_15/2),～521 nm (²H_11/2→⁴I_15/2),～537 nm (⁴S_3/2→⁴I_15/2),～652 nm (⁴F_9/2→⁴I_15/2).Therefore,cy- an-white light were observed by naked-eye under 980 nm excitation even for a low excitation power density. With increasing of the excitation power,the emissions firstly become stronger,then weaker,at last nearly dis- appear.There are some discussions on the tempe-rature-dependent upconversion emission spectra,too.Crys- tallization became well after higher temperatures annealing,and all emissions of Tm³⁺ and Er³⁺ become rela- tively stronger.Upeonversion spectra depending on Tm³⁺ concentration indicate that at relatively low Tm³⁺ concentration,Tm³⁺-Er³⁺ interaction is dominant,and all Er³⁺ emissions become stronger for Tm³⁺ transfer energy to Er³⁺.When Tm³⁺ concentration reaches about 0.3%,Tm³⁺-Tm³⁺ cross relaxation is dominant, and Er³⁺ emission relatively become weaker.All Tm³⁺ emissions become relatively stronger with Tm³⁺ con- eentration increasing.From the experimental results,we concluded that the YF₃ powders should be promising materials for up-conversion white light and three-dimensional solid display.更多还原