摘要
采用水热法通过调控n(F-)∶n(Ln3+),pH值以及n(Citrate)∶n(Ln)等一系列反应条件,合成了六方相的NaGdF4∶Yb3+,Ho3+与GdF3∶Yb3+,Ho3+纳米上转换材料,实现了形貌的可控合成。利用X射线粉末衍射(XRD),场扫描电子显微镜(SEM)以及发光光谱等手段对产物的物相结构、形貌和荧光性质进行了研究。在980 nm光激发下,六方相的NaGdF4∶Yb3+,Ho3+与GdF3∶Yb3+,Ho3+样品均显示出绿光(541 nm)和红光(647 nm)发射,分别来自于Ho3+的5F4,5S2→5I8和5F5→5I8的跃迁。结果显示NaGdF4∶Yb3+,Ho3+六棱柱与六棱片结构的发光远强于GdF3∶Yb3+,Ho3+的发光,但在pH=7.0,9.0时生成的NaGdF4∶Yb3+,Ho3+球形结构发光效率低于GdF3∶Yb3+,Ho3+。这表明六方相NaGdF4∶Yb3+,Ho3+不同形貌样品的尺寸与结晶性对发光效率影响很大。
The up-conversion NaGdF4∶Yb3＋,Ho3＋ and GdF3∶Yb3＋,Ho3＋ nanocrystals were successfully prepared by hydrothermal method.The samples were characterized by X-ray powder diffraction（XRD）,scanning electron microscopy（SEM） and luminescence spectra.The crystal structure and morphology can be well controlled by adjusting the molar ratio of n（F-）∶n（Ln3＋）,the value of pH and the molar ratio of n（Citrate）∶n（Ln）.The hexagonal NaGdF4∶Yb3＋,Ho3＋ and GdF3∶Yb3＋,Ho3＋ samples exhibit green（541 nm）and red（647 nm）emissions under 980 nm excitation,which are assigned to the transition of 5F4,5S2→5I8 and 5F5→5I8 in Ho3＋,respectively.It was found that the upconversion efficiency of the hexagonal prism and flake NaGdF4∶Yb3＋,Ho3＋ samples are much stronger than that of GdF3∶Yb3＋,Ho3＋ samples,but the spherical NaGdF4∶Yb3＋,Ho3＋ samples are weaker than GdF3∶Yb3＋,Ho3＋ samples.This indicates that the upconversion efficiency of hexagonal NaGdF4∶Yb3＋,Ho3＋ samples are greatly impacted by the different size and crystalline for different morphology.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2011年第12期1233-1237,共5页
Chinese Journal of Luminescence
基金
国家自然科学基金(10834006
10774141
10904141
10904140)
国家科技部(2006CB601104)
吉林省科技发展计划(20090134
20090524)
中国科学院创新项目资助
