Lu_2O_3:Yb^(3+),Tm^(3+)纳米晶的结构和上转换发光性能研究

Structure and Upconversion Luminescent Properties of Lu_2O_3:Yb^(3+),Tm^(3+) Nanocrystals

采用共沉淀法制备了Yb3+和Tm3+共掺杂的Lu2O3纳米晶,用X射线衍射(XRD)、场发射扫描电子显示镜(SEM)和上转换光谱对样品进行了表征。研究了Tm3+浓度和煅烧温度对粉末的结构和上转换发光性能的影响。结果表明,制备出的纳米晶具有纯的Lu2O3相,结晶性较好。在980 nm半导体激光器激发下,样品发射出蓝光、红光和近红外光,并且当Tm3+掺杂摩尔分数超过0.2%时,出现了浓度猝灭效应。随着煅烧温度的增加,纳米晶的尺寸增大,上转换发光强度增强。发射强度与激发功率的关系表明,蓝光490 nm和红光653 nm的发光是三光子过程,近红外811 nm的发光是双光子过程。

Lutetium oxide nanocrystals codoped with Tm3＋ and Yb3＋ were synthesized by the co-precipitation method.The obtained samples were characterized by X-ray diffraction（XRD）,field emission scanning electron microscope（FE-SEM） and upconversion spectra measurements.Effect of the Tm3＋ molar concentration and calcination temperature on the structure and upconversion luminescent properties of the nanocrystals have been investigated.The XRD results show that all the samples can be readily indexed to pure cubic phase of Lu2O3 and indicates good crystallinity.The experimental results show that concentration quenching occurs when the doping mole fraction of Tm3＋ is above 0.2%.Blue,red and near infrared emissions from the prepared samples have been observed at 980 nm laser excitation.With the increase of the calcination temperature,the grain sizes and upconversion emission intensity of nanocrystals increase.Power-dependent investigation reveals that the blue（490 nm） and red（653 nm） upconversion fluorescence is three-photon upconversion process.The near infrared（811 nm） upconversion fluorescence is a two-photon upconversion process.