Huang Liu, Wan Xiaodong, Rong Hongpan, Yao Yuan, Xu Meng, Liu Jia, Ji Muwei, Liu Jiajia, Jiang Lan, Zhang Jiatao
Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China.
Institute of Physics, Chinese Academy of Science, Beijing, 100190, China.
Small. 2018 Apr;14(16):e1703501. doi: 10.1002/smll.201703501. Epub 2018 Feb 12.
High-efficient charge and energy transfer between nanocrystals (NCs) in a bottom-up assembly are hard to achieve, resulting in an obstacle in application. Instead of the ligands exchange strategies, the advantage of a continuous laser is taken with optimal wavelength and power to irradiate the film-scale NCs superlattices at solid-liquid interfaces. Owing to the Au-based NCs' surface plasmon resonance (SPR) effect, the gentle laser irradiation leads the Au NCs or Au@CdS core/shell NCs to attach each other with controlled pattern at the interfaces between solid NCs phase and liquid ethanol/ethylene glycol. A continuous wave 532 nm laser (6.68-13.37 W cm ), to control Au-based superlattices, is used to form the monolayer with uniformly reduced interparticle distance followed by welded superstructures. Considering the size effect to Au NCs' melting, when decreasing the Au NCs size to ≈5 nm, stronger welding nanostructures are obtained with diverse unprecedented shapes which cannot be achieved by normal colloidal synthesis. With the help of facile scale-up and formation at solid-liquid interfaces, and a good connection of crystalline between NCs, the obtained plasmonic superstructured films that could be facilely transferred onto different substrates exhibit broad SPR absorption in the visible and near-infrared regime, enhanced electric conductivities, and wide applications as surface enhanced Raman scattering (SERS)-active substrates.
在自下而上的组装过程中，纳米晶体（NCs）之间高效的电荷和能量转移很难实现，这成为了应用中的一个障碍。与配体交换策略不同，利用连续激光的优势，选择最佳波长和功率，在固液界面处照射薄膜尺度的NCs超晶格。由于基于金的NCs的表面等离子体共振（SPR）效应，温和的激光照射使金NCs或金@硫化镉核壳NCs在固体NCs相和液体乙醇/乙二醇的界面处以可控模式相互附着。使用连续波532nm激光（6.68 - 13.37W/cm²）来控制基于金的超晶格，形成单层结构，其粒子间距离均匀减小，随后形成焊接超结构。考虑到尺寸对金NCs熔化的影响，当将金NCs尺寸减小到约5nm时，可获得更强的焊接纳米结构，呈现出各种前所未有的形状，这是常规胶体合成无法实现的。借助在固液界面处的简便放大和形成过程，以及NCs之间良好的晶体连接，所获得的等离子体超结构薄膜能够轻松转移到不同基板上，在可见光和近红外区域表现出宽SPR吸收、增强的电导率，并作为表面增强拉曼散射（SERS）活性基板具有广泛应用。
