Ba5Zn4Y8O21:Ho^3+,Yb^3+上转换发光粉的制备与发光性能研究

为实现以Ba5Zn4Y8O21为基质的上转换三基色发光,采用固相合成法于1200℃下制备了Ba5Zn4Y8O21:Ho^3+,Yb^3+发光粉,并对其绿光发射特性进行了研究。980 nm激发下的上转换发射光谱测试结果证实,最佳掺杂浓度下的Ba5Zn4Y8O21:14%Yb^3+,0.15%Ho^3+主要呈现5S2/5F4→5I8跃迁所致的548、553 nm绿光发射,而5F5→5I8和5S2/5F4→5I7跃迁产生的664、758nm红光和近红外光发射非常微弱。而且,绿光强度随激发功率呈线性变化,在20.7 mW/cm^2功率密度范围内,绿红光分支比最高达13.16,呈现优异的色纯度。上转换发光热稳定性测试结果表明,样品的发光效率随样品温度的升高略有下降,50℃时发光强度降低仅9.75%。上述结果证实,Ba5Zn4Y8O21:Ho^3+,Yb^3+是一种优质的绿光上转换发光材料。

Synthesis and luminescence properties of Ba5Zn4Y8O21:Ho^3+,Yb^3+upconversion phosphor

Ba5Zn4Y8O21:Ho^3+,Yb^3+up conversion(UC)phosphors were prepared by solid-state method at 1200℃in order to obtain the UC tricolor luminescence based on Ba5Zn4Y8O21.The green emission characteristics of the phosphors were studied under 980 nm excitation.Spectrum measurement results confirmed that the phosphor with optimum doping concentration exhibited strong green emissions located at 548 nm and 553 nm which corresponded to the 5S2/5F4→5I8 transfers of Ho^3+ion.Moreover,very weak red and infrared emissions located at 664 nm and 758 nm could also be observed.These two emissions could be attributed to 5F5→5I8 and 5S2/5F4→5I7 transfers of Ho^3+ion,respectively.Furthermore,the green emission intensity changed linearly with the excitation power and no decreasing tendency was observed in the test range.Consequently,large intensity ratio value of green and red emissions(IG/IR)was obtained,showing excellent color purity.The thermal stability measurement results of the UC luminescence showed that the luminescence efficiency of the phosphor decreased slightly with the increase of the phosphor temperature.When the temperature rose to 50°C,the luminescence intensity decreased only 9.75%.The above results confirmed that Ba5Zn4Y8O21:Ho^3+,Yb^3+was a high-quality green up conversion luminescent material.