YAG:Yb~(3+),Tm~(3+)纳米晶粉体的制备及其蓝色上转换发光

以稀土氧化物、硝酸铝为原料,采用溶胶-凝胶法合成了Yb3+、Tm3+共掺的钇铝石榴石(Y3Al5O12,YAG)纳米晶粉体。采用X射线衍射(XRD)确定了1200℃煅烧后的晶体粉为纯YAG结构,无杂质相,晶体尺寸约为90nm;该粉体在波长为980nm的半导体激光器激发下发射出中心波长为487nm的蓝色上转换荧光,对应于Tm3+离子的1G4→3H6的跃迁。发光强度和激发功率关系的研究揭示了其为双光子过程,Tm3+的激发态吸收及Tm3+、Yb3+间的交叉驰豫型能量传递和是该上转换发光的主要机制。

Synthesis of YAG: Yb~(3+) ,Tm~(3+)and its blue upconversion luminescence

Yb~(3+) ,Tm~(3+) co-doped Yttrium aluminum gamet(Y_3Al_5O_(12), YAG) nanocrystal powders were synthe-sized by a sol-gel process from a mixed solution containing aluminum nitrates and rare-earth oxides. XRD technique was used to characterize struetures of sample and precursor. It was found that Mono-phase YAG crystallites were formed at 1200℃ without formation of any intermediate phase. Blue upconversion emission which centered at 487nm was detected under excitation of a 980nm diode laser. The blue emission was indicated to a two-photon processes and the upconversion mechanisms are determined to excited state absorption (ESA) of Tm~(3+) and cross relaxation (CR) between Yb~(3+) and Tm~(3+).