Zhang Dongshi, Gökce Bilal, Notthoff Christian, Barcikowski Stephan
Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitätsstraße 7, 45141, Essen, Germany.
Nanoparticle Process Technology and CENIDE, Faculty of Mechanical Engineering &Process Technology, University of Duisburg-Essen, Lotharstr. 1, D-47057 Duisburg, Germany.
Sci Rep. 2015 Sep 3;5:13661. doi: 10.1038/srep13661.
Hybrid particles are of great significance in terms of their adjustable optical, electronic, magnetic, thermal and mechanical properties. As a novel technique, laser ablation in liquids (LAL) is famous for its precursor-free, "clean" synthesis of hybrid particles with various materials. Till now, almost all the LAL-generated particles originate from the nucleation-growth mechanism. Seed-growth of particles similar to chemical methods seems difficult to be achieved by LAL. Here, we not only present novel patch-joint football-like AgGe microspheres with a diameter in the range of 1 ~ 7 μm achievable by laser ablation in distilled water but also find direct evidences of their layered seed growth mechanism. Many critical factors contribute to the formation of AgGe microspheres: fast laser-generated plasma process provide an excellent condition for generating large amount of Ge and Ag ions/atoms, their initial nucleation and galvanic replacement reaction, while cavitation bubble confinement plays an important role for the increase of AgGe nuclei and subsequent layered growth in water after bubble collapse. Driven by work function difference, Ge acts as nucleation agent for silver during alloy formation. This new seed-growth mechanism for LAL technique opens new opportunities to develop a large variety of novel hybrid materials with controllable properties.
混合粒子因其可调节的光学、电子、磁性、热学和力学性能而具有重要意义。作为一种新技术，液体中的激光烧蚀（LAL）以其无前驱体、“清洁”合成各种材料的混合粒子而闻名。到目前为止，几乎所有通过LAL生成的粒子都源于成核-生长机制。类似于化学方法的粒子种子生长似乎很难通过LAL实现。在这里，我们不仅展示了通过在蒸馏水中进行激光烧蚀可实现的直径在1~7μm范围内的新型补丁连接足球状AgGe微球，还发现了它们分层种子生长机制的直接证据。许多关键因素促成了AgGe微球的形成：快速的激光产生的等离子体过程为大量的Ge和Ag离子/原子的产生、它们的初始成核和电偶置换反应提供了良好的条件，而空化气泡限制对于AgGe核的增加以及气泡坍塌后在水中的后续分层生长起着重要作用。在功函数差异的驱动下，Ge在合金形成过程中作为银的成核剂。这种LAL技术的新种子生长机制为开发各种具有可控性能的新型混合材料开辟了新机会。
