高量子效率的近红外量子裁剪材料LaF_3∶Ho^(3+),Yb^(3+)的合成及其发光性能

Highly Efficient Near-Infrared Quantum Cutting in LaF_3∶Ho^(3+),Yb^(3+) for Solar Cells

采用共沉淀法合成了LaF3∶Ho3+,Yb3+红外下转换材料,研究了室温下该材料的激发光谱、发射光谱特性和发光的时间衰减曲线。在LaF3∶Ho3+,Yb3+粉末中,观察到了Ho3+到Yb3+的能量传递,并通过分析确认了其为共振能量传递。通过Ho3+到Yb3+的共振能量传递过程,可以将材料吸收一个300～360 nm波段的紫外光子转化为两个波长在1μm附近的红外光子。Yb3+的发射正好与硅太阳能电池的吸收匹配,材料中的这一红外下转换现象对于提高硅太阳能电池的效率具有积极意义。

LaF3 Crystalline powders doped with Ho^3＋and Yb^3＋ were prepared by co-precipitation method.The samples were characterized by XRD.Single-phase LaF3∶Ho^3＋,Yb^3＋ powders with hexagon structure were obtained in our experimental process.Excitation spectra,emission spectra,and decay curves were used to characterize the samples at room temperature.The energy transfer from Ho^3＋ to Yb^3＋ was confirmed.Further it is recognized as a resonant energy transfer process.Through the process,the samples could absorb ultraviolet photons with 300-360 nm band and emit two near-infrared photons around 1 μm.This result reveals the possibility of violet to near-infrared quantum cutting with a quantum efficiency larger than 100% in Ho^3＋/ Yb^3＋ co-doped fluorides,suggesting the possible application in modifying the solar spectrum to enhance the efficiency of silicon solar cells.