Gd3+,Yb3+和Tm3+共掺杂氟化物纳米晶中Yb3+-Tm3+-Gd3+间的能量传递

用水热法合成了Y_0.8-x-yF₃∶Gd_x³⁺,Yb_0.2³⁺,Tm_y³⁺纳米晶的上转换发光材料。在典型的Y_0.595F₃∶Gd_0.200³⁺,Yb_0.200³⁺, Tm_0.005³⁺纳米微晶中,在980 nm激光激发下,观察到了Tm³⁺的紫外、紫色上转换发射明显增强和来自于Gd³⁺的⁶D_9/2、⁶I_J、⁶P_5/2及⁶P_7/2能级到基态⁸S_7/2能级的紫外发射。通过比较Y_0.8-x-yF₃∶Gd_x³⁺ ,Yb_0.2³⁺,Tm_y³⁺纳米晶样品的上转换发光性质以及Tm³⁺和Gd³⁺中一些激发态的能级寿命,借助于能级图描述了Yb³⁺-Tm³⁺-Ga³⁺之间的有效的能量传递过程。

Energy Transition Processes between Yb~(3+)-Tm~(3+)-Gd~(3+) in Gd~(3+),Yb~(3+) and Tm~(3+) Co-dopedg Fluoride Nanocrystal

Y_0.8-x-yF₃∶Gd_x³⁺, Yb_0.2³⁺,Tm_y³⁺ nanocrystals were synthesized through a hydrothermal method. The upconversion(UC) emission properties under a 980 nm continuous wave semiconductor laser diode excitation were studied. The experimental results suggested that the violet and ultraviolet(UV) UC emission enhancement were observed in Y_0.595F₃∶Gd_0.200³⁺,Yb_0.200³⁺,Tm_0.005³⁺ nanocrystal,as well as the UC emissions of Gd³⁺ of ⁶D_9/2,⁶I_J,⁶P_5/2,and ⁶P_7/2 states to the ground state ⁸S_7/2 were shown,too. The luminescent kinetic analysis implied that,under 980 nm excitation,Yb³⁺ can transfer energy to populate the ³P₂ level of Tm³⁺,make UV,violet,and blue UC emissions obtained,further,the ⁶I_J multiplets of Gd³⁺ were populated through the energy transfer process ³P₂→³H₆(Tm³⁺):⁸S_7/2→⁶I_J(Gd³⁺). At the same time,the energy transfer processes occurred between Gd³⁺ and Yb³⁺ or Tm³⁺ based on the energy matching conditions, leading to the above mentioned UV UC emissions of Gd³⁺.