Liu Dilong, Li Cuncheng, Zhou Fei, Zhang Tao, Zhang Honghua, Li Xinyang, Duan Guotao, Cai Weiping, Li Yue
1] Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, P. R. China [2] Department of Materials Science &Engineering, University of Science and technology of China, Hefei 230026, P. R. China.
Key Laboratory of Chemical Sensing &Analysis in Universities of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, Shandong, P. R. China.
Sci Rep. 2015 Jan 8;5:7686. doi: 10.1038/srep07686.
We develop a facile and effective strategy to prepare monodispersed Au spherical nanoparticles by two steps. Large-scale monocrystalline Au nanooctahedra with uniform size were synthesized by a polyol-route and subsequently Au nanoparticles were transformed from octahedron to spherical shape in a liquid under ambient atmosphere by non-focused laser irradiation in very short time. High monodispersed, ultra-smooth gold nanospheres can be obtained by simply optimizing the laser fluence and irradiation time. Photothermal melting-evaporation model was employed to get a better understanding of the morphology transformation for the system of nanosecond pulsed-laser excitation. These Au nanoparticles were fabricated into periodic monolayer arrays by self-assembly utilizing their high monodispersity and perfect spherical shape. Importantly, such Au nanospheres arrays demonstrated very good SERS enhancement related to their periodic structure due to existence of many SERS hot spots between neighboring Au nanospheres caused by the electromagnetic coupling in an array. These gold nanospheres and their self-assembled arrays possess distinct physical and chemical properties. It will make them as an excellent and promising candidate for applying in sensing and spectroscopic enhancement, catalysis, energy, and biology.
我们开发了一种简便有效的策略，通过两步法制备单分散的金球形纳米颗粒。通过多元醇路线合成了尺寸均匀的大规模单晶金纳米八面体，随后在环境气氛下的液体中，通过非聚焦激光照射在极短时间内将金纳米颗粒从八面体转变为球形。通过简单地优化激光能量密度和照射时间，可以获得高度单分散、超光滑的金纳米球。采用光热熔蒸发模型来更好地理解纳秒脉冲激光激发体系的形貌转变。利用这些金纳米颗粒的高单分散性和完美的球形，通过自组装将它们制成周期性单层阵列。重要的是，由于阵列中相邻金纳米球之间存在许多由电磁耦合引起的表面增强拉曼散射（SERS）热点，这种金纳米球阵列因其周期性结构而表现出非常好的SERS增强效果。这些金纳米球及其自组装阵列具有独特的物理和化学性质。这将使它们成为传感和光谱增强、催化、能源及生物学应用方面优秀且有前景的候选材料。
