Recently, Prof. LI Yue from Institute of Solid State Physics (ISSP), Hefei Institutes of Physical Science made a new progress in the capillary gradient-induced self-assembly of periodic Au spherical nanoparticle arrays on an ultra-large scale via a bi-solvent system at air/water interface. This related result has been published in Advanced Materials Interfaces.
Regular assemblies of Au nanoparticles (NPs) into 2D monolayer film have received increasing attention in recent years because of their potential applications in chemical and biological sensors, photocatalysis, and photonic/electronic devices.
Traditional self-assembling approaches to fabricate Au NP array films include the Langmuir¨CBlodgett (LB) technique and oil¨Cwater interfacial self-assembly technique.
While, the LB technique needs special and precise equipment, and is usually limited to hydrophobic NPs. And the oil¨Cwater interfacial self-assembly is only suitable for hydrophilic NPs, and the formed NP array film is fragile and can break easily when the oil phase completely evaporates.
More recently, the direct self-assembly technique at air/water interface was tried to prepare a 2D ordered monolayer with large scale. However, achieving self-assembly of highly ordered 2D Au nanosphere array on an ultra-large scale remains a great challenge.
To overcome such challenge, LI¡¯s group developed a capillary gradient-induced self-assembly strategy to organize monodispersed Au nanospheres into periodic dense 2D Au nanosphere arrays over a centimeter-sized scale at the air/water interface.
This presented strategy possesses advantages of having a simple operation and being environment-friendly.
By using such a capillary gradient-induced self-assembly technique, it is easy to obtain Au nanosphere arrays with long-range HCP ordering at the air/water interface, which could be facilely transferred onto desirable substrates. The assembled Au NP arrays could provide a promising and important platform for practical applications in biosensors and catalysis because of the unique size-, shape-, and dielectric-dependent optical properties of Au NPs.
This research work is supported by the National Basic Research Program of China, Natural Science Foundation of China, Cross-disciplinary Collaborative Teams and International Innovative Research Team in CAS of CAS.
Link to the paper£ºhttp://onlinelibrary.wiley.com/doi/10.1002/admi.201600976/full
Figure 1. Schematic of fabrication of HCP and centimeter-sized 2D nanosphere array film of Au NPs by a capillary gradient-induced self-assembly technique on air/water interfaces.£¨Image by LIU Dilong£©
Figure 2. a) Photographs of self-assembled Au nanosphere array film that was floated on water surface and then transferred onto a silicon substrate (bottom-right inset). Photographs of formed Au nanosphere array film transferred onto quartz substrate and flexible PDMS substrate , respectively. b) Photographs of the fishing process for the Au monolayer film transferred onto a quartz substrate. c¨Cd) SEM images of self-assembled Au nanosphere array film in top view (c) and tilted view (d). £¨Image by LIU Dilong£©
Prof. LI Yue
Institute of Solid State Physics, CAS
Fax: 0551-65591434, Tel: 0551-65595323