Zeng Haibo, Cai Weiping, Li Yue, Hu Jinlian, Liu Peisheng
Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academia of Sciences, Hefei, 230031, P. R. China.
J Phys Chem B. 2005 Oct 6;109(39):18260-6. doi: 10.1021/jp052258n.
We present composition-controlled synthesis of ZnO-Zn composite nanoparticles by laser ablation of a zinc metal target in pure water or in aqueous solution of sodium dodecyl sulfate (SDS). By SDS concentration, composition and size of the nanoparticles can be controlled in a wide range. Relative amounts of the components Zn and ZnO, the particle size, and the microstructure can evolve with SDS concentration in solution. High SDS concentration corresponds to high relative amount of Zn nanoparticles existing as the core in the core/shell nanostructures, whereas low SDS concentration leads to high ZnO amount. This was explained by a dynamic mechanism on the basis of the competition between aqueous oxidation and SDS capping protection. Correspondingly, optical absorption spectra evolve from the excitonic peak of ZnO (about 350 nm) to the Zn surface plasmon resonance (about 242 nm) with rise of SDS concentration. A blue (about 450 nm) photoluminescence was observed in the obtained ZnO nanoparticles, which was attributed to existence of interstitial zinc in ZnO lattices. This study has revealed that laser ablation of active metal in liquid media is an appropriate method to synthesize a series of metal oxide semiconductor-metal composite nanoparticles with controlled composition and size.
我们展示了通过在纯水或十二烷基硫酸钠（SDS）水溶液中激光烧蚀锌金属靶来合成成分可控的ZnO-Zn复合纳米颗粒。通过SDS浓度，可以在很宽的范围内控制纳米颗粒的成分和尺寸。颗粒中Zn和ZnO组分的相对含量、粒径以及微观结构会随着溶液中SDS浓度的变化而演变。高SDS浓度对应于核壳纳米结构中以Zn纳米颗粒为核的高相对含量，而低SDS浓度则导致高ZnO含量。这是基于水相氧化和SDS封端保护之间竞争的动态机制来解释的。相应地，随着SDS浓度的增加，光吸收光谱从ZnO的激子峰（约350 nm）演变为Zn的表面等离子体共振（约242 nm）。在所制备的ZnO纳米颗粒中观察到了蓝色（约450 nm）光致发光，这归因于ZnO晶格中存在间隙锌。该研究表明，在液体介质中激光烧蚀活性金属是合成一系列成分和尺寸可控的金属氧化物半导体-金属复合纳米颗粒的合适方法。
