Hu He, Chen Zhigang, Cao Tianye, Zhang Qiang, Yu Mengxiao, Li Fuyou, Yi Tao, Huang Chunhui
Department of Chemistry and Laboratory of Advanced Materials, Fudan University, 220 Handan Road, Shanghai 200433, People's Republic of China.
Nanotechnology. 2008 Sep 17;19(37):375702. doi: 10.1088/0957-4484/19/37/375702. Epub 2008 Aug 1.
Hexagonal Yb/Er or Yb/Ho co-doped LaF(3) nanoplates with uniform morphology have been synthesized with an average diameter of ∼15 nm. It was found that the coating reagent, hydrothermal temperature and time play critical roles in the control of the shape of the final products. A possible growth mechanism including ion exchange, 'burst-nucleation', and 'heat-up' growth is proposed. (1)H NMR spectra and Fourier transform infrared (FTIR) spectra indicate that the surface of the nanoplates is coated with oleic acid ligands. Those hexagonal nanoplates display the capability of forming self-assembled two-dimensional nanoarrays. Moreover, under continuous-wave excitation at 980 nm, the LaF(3):12%Yb,3%Er nanoplates exhibited bright orange emission (a combination of green between 515 and 556 nm and red between 640 and 675 nm) and the LaF(3):20%Yb,1%Ho nanoplates had nearly pure green upconversion luminescence between 530 and 554 nm. The intensity of upconversion luminescence increased with time and increase of the hydrothermal temperature. For the bright upconversion luminescence, the as-prepared samples show potential applications in color displays, the building of nanodevices and as biolabels.
已合成出具有均匀形态的六边形镱/铒或镱/钬共掺杂氟化镧（LaF₃）纳米片，平均直径约为15纳米。发现包覆试剂、水热温度和时间在最终产物形状的控制中起着关键作用。提出了一种可能的生长机制，包括离子交换、“爆发成核”和“升温”生长。¹H NMR光谱和傅里叶变换红外（FTIR）光谱表明，纳米片表面包覆有油酸配体。那些六边形纳米片具有形成自组装二维纳米阵列的能力。此外，在980纳米的连续波激发下，LaF₃:12%Yb,3%Er纳米片呈现出明亮的橙色发射（515至556纳米之间的绿色和640至675纳米之间的红色的组合），而LaF₃:20%Yb,1%Ho纳米片在530至554纳米之间具有近乎纯的绿色上转换发光。上转换发光强度随时间和水热温度的升高而增加。对于明亮的上转换发光，所制备的样品在彩色显示、纳米器件构建和生物标记方面显示出潜在应用。
