【摘要】 采用高温固相法制备了一系列的NaY_0.78-x（MoO₄）₂∶0.2Yb³⁺,0.02Ho³⁺,xZn²⁺（x=0,0.05,0.1,0.15,0.2,0.25）荧光粉。通过X射线衍射仪、扫描电镜以及荧光光谱仪分别对样品的结构、形貌和荧光性能进行了表征。结果表明Zn²⁺的掺杂可以通过替换Y³⁺格位和占据晶格间隙的方式进入基质晶格。在980nm激光激发下,样品呈现出了强烈的绿光（551nm）和相对微弱的红光发射（668nm）,分别归因于Ho³⁺的⁵F₄,⁵S₂→⁵I₈和⁵F₅→⁵I₈跃迁。Zn²⁺的掺杂可以使上转换发光强度显著增强,其原因是Zn²⁺掺杂产生了O^2-空位而且可以裁剪Ho²⁺周围的局域晶体场对称性。基于泵浦依赖的研究,对能级图和可能的上转换发光机理进行了详细的讨论。更多还原

【Abstract】 A series of NaY_0.78-x（MoO₄）₂∶0.2Yb³⁺, 0.02Ho³⁺,xZn²⁺（x=0, 0.05, 0.1, 0.15, 0.2, 0.25） phosphors were synthesized by a high-temperature solid-state reaction method. The phase purity, morphology and luminescence properties of samples were characterized by XRD, SEM and luminescence spectrometer, respectively. The results indicate that Zn²⁺ ions introduced into the host lattice through occupying Y³⁺sites or the interstitial sites. Under the excitation of 980nm laser diode, the intense green（551nm） and weak red（668nm） emissions were observed, which could be assigned to the⁵F₄,⁵S₂→⁵I₈ and ⁵F₅→⁵I₈ transitions of Ho³⁺ ions.The upconversion emission intensity is found being significantly enhanced by doping Zn2+ions, which may be due to the oxygen vacancy generated by Zn²⁺ ions incorporation in the lattices and modification of the local symmetry of the Ho³⁺ ions. Based on the pump-power dependence, the energy level diagram was illustrated and possible energy transfer mechanisms were discussed in detail.更多还原