Zhang Wei-Wei, Zhang Wei-Ping, Xie Ping-Bo, Yin Min, Chen Hou-Tong, Jing Long, Zhang Yun-Sheng, Lou Li-Ren, Xia Shang-Da
Structure Research Laboratory, University of Science and Technology of China, Academia Sinica, 230026 Hefei, People's Republic of China.
J Colloid Interface Sci. 2003 Jun 15;262(2):588-93. doi: 10.1016/S0021-9797(03)00169-3.
The structure of nanocrystalline Y2O3:Eu prepared by a combustion reaction was analyzed by XRD and high-resolution electron microscopy. Compared with a large-scale particles, 5-nm Y2O3:Eu particles presented as distorted crystallite and rough surfaces. Luminescent and absorption properties of nano-Y2O3:Eu showed remarkably particle size effects. At Y2O3:Eu particle sizes smaller than 10 nm some new results were observed: (a) a red shift of the charge-transfer-state absorption; (b) new emission bands of Eu3+ in the 5D0 --> 7F2 region; (c) luminescent decay of energy level 5D0 of Eu3+ turning to a two-step exponential; and (d) a pronounced increase in quenching concentration and much lower phonon density compared with those of the bulk material. All these phenomena can be attributed to the effect of the softened lattice and surface state of the nanomaterial. The latter was confirmed by stronger excitation by the host absorption after the surface modification.
通过燃烧反应制备的纳米晶Y2O3:Eu的结构用XRD和高分辨率电子显微镜进行了分析。与大尺寸颗粒相比，5纳米的Y2O3:Eu颗粒呈现出扭曲的微晶和粗糙的表面。纳米Y2O3:Eu的发光和吸收特性表现出显著的粒径效应。在Y2O3:Eu粒径小于10纳米时，观察到了一些新结果：(a)电荷转移态吸收的红移；(b)Eu3+在5D0→7F2区域的新发射带；(c)Eu3+的5D0能级的发光衰减转变为两步指数衰减；(d)与块状材料相比，猝灭浓度显著增加且声子密度低得多。所有这些现象都可归因于纳米材料晶格软化和表面态的影响。表面改性后主体吸收的更强激发证实了后者。
