球形Y_2O_2S∶Yb,Ho上转换粒子的合成及其尺寸相关的发光机制研究  

Preparation and Size-dependent Upconversion Luminescence Mechanism of Y_2O_2S∶Yb,Ho Nanoparticles

作　　者：邢明铭[1] 曹望和[1] 冯威[1] 庞涛[1] 凌小翘[1] 

机构地区：[1]大连海事大学光电子技术研究所,大连116026

出　　处：《高等学校化学学报》2009年第9期1696-1702,共7页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:10374011)资助

摘　　要：采用改进的均匀沉淀法结合固-气硫化工艺制备了一系列Y2O2S∶Yb,Ho上转换粒子.利用X射线晶体衍射(XRD)和透射电子显微镜(TEM)对粒子的结构和形貌进行了表征,并通过上转换发光光谱(UCL)和红外光谱(FTIR)研究了粒子的上转换发光性质.XRD和TEM结果表明,所制备的样品均为单一的六方相结构,且所有粒子均呈单分散和尺寸均一的球形,其尺寸分别为40,80和200nm.根据发光强度和激发功率间的对数关系曲线发现,随着粒子尺寸的降低,蓝光发射由三光子吸收过程转变为双光子吸收过程;而绿光和红光发射虽然一直保持双光子吸收过程,但其对数曲线斜率均随粒子尺寸的降低而逐渐增大.对该材料的粒子尺寸与上转换发光机制的关系进行了讨论.A series of Y2O2S： Yb, Ho upeonversion particles were prepared using an improved homogeneous precipitation method combined with a solid-gas sulfuration technology. The structure and morphology of particles were characterized by X-ray diffraction（XRD） and transmission electron microscope（ TEM）, and the upconversion luminescence （UCL） properties and mechanisms were studied by UCL spectra and FT-infrared spectra（FTIR）. The results of XRD indicated that the prepared samples were pure hexagonal structure. TEM images showed the prepared particles were mono-dispersed with regular sphere shape and exhibited the narrow size distribution with average size of 40, 80 and 200 nm, respectively. According to the ln-ln plots of emission intensity as a function of excitation power, it was found that the blue emissions varied from three-photon absorption process to two-photon absorption process with decreasing particle size. For the green and red emissions, only the two-photon absorption process was observed, but the slope values of the lnIP-lnIUCL plot increased with decreasing particle size. The mechanism of the effects of particle size on the UCL properties was discussed.

关 键 词：上转换 发光机制 Y2O2S∶Yb Ho 

分 类 号：O614.33[理学—无机化学]