Yb3 +-Er3+-codoped fluoride samples were synthesized by using solid-state reaction method. Upconversion emission characters were investingated under 980 nm laser diode excitation. It was found that the upconversion spectra depended on excited power when Yb3+ -doped content was more than 10%. According to various concentration of rear-earth ions, an upconversion process with time-delayed sequential two-phonon energy tansfer was proposed, which can be able lo explain the phenomenon satisfactorily.%用固相法合成了Er3+和Yb3+共掺的LaF3及NaYbF4上转换发光粉末样品材料,研究了激发功率对室温上转换发光性质的影响,重点研究了红光发射增强现象,并探讨了获得红色上转换发光的条件.实验结果表明:在980 nm半导体激光激发下,Er3+和Yb3+共同掺杂的不同氟化物样品材料能够展示比较明亮的红色和绿色发光,激发功率密度对该类材料的上转换红色发射光谱性质能够产生明显的影响.基于上转换发光机制,提出了能量传递的红色上转换发射过程,并借助于一个示意性的能级图解释了所观测到的红色上转换发射增强现象.
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