共沉淀法制备Y2SiO5∶Er3+ ,Yb3+ ,Tm3+及其上转换发光性能研究

采用化学共沉淀法制备了系列Y_1.98-2xYb_2x Er_0.02SiO₅(0.00≤x≤0.15)以及Y_1.736Yb_0.24Er_0.02Tm_0.004SiO₅上转换发光材料,比较了室温下Y_1.98-2xYb_2x Er_0.02 SiO₅ (x=0.00,0.08)样品在400—1600 nm范围内的吸收光谱,测量了所有样品在976 nm OPO激光器激发下的上转换发射光谱,以及Er³⁺离子⁴S_3/2(⁴F_9/2)→⁴I_15/2,Tm³⁺离子¹G₄→³H₆荧光衰减曲线和不同激发功率下的上转换蓝光发射强度,从而分析讨论了Er³⁺,Tm³⁺在Y₂SiO₅中的上转换发光机理.研究结果表明:在1250 ℃相对较低的温度下合成了X2型单斜晶系Y₂SiO₅ ∶Ln³⁺(Ln³⁺=Er³⁺,Yb³⁺,Tm³⁺),Yb³⁺的敏化显著增强了样品在976 nm附近的吸收能力,并大幅度加宽了该处的吸收带.分析上转换发射光谱发现:上转换绿光和红光强度都随着Yb³⁺浓度的增加先增强后减弱,但红光的猝灭浓度较高,归因于Er³⁺→Yb³⁺反向能量传递ETU4和Yb³⁺→Er³⁺正向能量传递ETU3过程的发生;上转换蓝光发射是三光子吸收过程,是通过Yb³⁺,Tm³⁺之间三次声子辅助的能量转移方式实现的. 关键词： 上转换 共沉淀 2SiO₅∶Er³⁺')" href="#">Y₂SiO₅∶Er³⁺ 3+')" href="#">Yb³⁺ 3+')" href="#">Tm³⁺

Upconversion luminescence properties of Y2 SiO5: Er3+,Yb3 +, Tm3+ synthesized by co-precipitation method

A series of up-conversion luminescence materials of Y_1.98-2xYb_2xEr_0.02SiO₅(0.00≤x≤0.15) and Y_1.736Yb_0.24Er_0.02Tm_0.004SiO₅ were synthesized by co-precipitation method.The absorption spectra from 400 to 1600 nm of Y_1.98-2xYb_2x Er_0.02SiO₅ (x=0.00,0.08) were compared, and the up-conversion emission spectra of all samples were investigated when excited by 976 nm opo laser. The decay curves of Er³⁺⁴S_3/2(⁴F_9/2)→ ⁴I_15/2,Tm³⁺¹G₄→³H₆,as well as the relationship between the blue up-conversion emission intensity and pumping power were measured,consequently, the possible up-conversion luminescence mechanisms of Er³⁺,Tm³⁺ in Y₂SiO₅ were discussed. The results show that X2-type monoclinic Ln³⁺(Ln³⁺=Er³⁺,Yb³⁺,Tm³⁺) co-doped Y₂SiO₅ phosphors have been synthesised under relatively low temperature of 1250 ℃, and the absorption intensity and bandwidth are remarkably increased by Yb³⁺ sensitizing around 976 nm. Up-conversion emission spectra has been analyzed and the results suggest that both the green and red lights increase first and then decrease with the increase of the Yb³⁺ doping concentration. However,the concentration quenching of the red light emission is higher, due to the forward (ETU3) and back (ETU4) energy transfer between Yb³⁺ and Er³⁺ ions; the blue emission occurs mainly through phonon-assisted energy transfer between Yb³⁺ and Tm³⁺ ions, which is a three photon absorption process.