[Chem. Mater.] Light-Controlled Shrinkage of Large-Area Gold Nanoparticle Monolayer Film for Tunable SERS Activity
作者：Xuefei Lu, YJ Huang*, BQ Liu, L Zhang, LP Song, JW Zhang, AF Zhang, Tao Chen*
關鍵字：Au NPs, UV, Interface self-assembly
論文來源：期刊
具體來源：Chem. Mater. 2018, Inpress
發表時間：2018年
The two-dimensional (2D) monolayer gold nanoparticle (Au NP) film is of significant interest and importance in both fundamental and practical applications including optoelectronic devices, sensing, catalysis, and surface-enhanced Raman spectroscopy (SERS). Because of
the weak physical interaction, the conventional monolayer Au NP film fabricated at the oil?water interface was unstable, easily breakable, and difficultly transferred. In the present
work, we report on a simple and effective chemical crosslinking strategy at the air?water interface to achieve a largescale monolayer gold nanoparticle film with intelligently tunable size of nanogaps, and excellent free-standing and easily transferable properties. In our strategy, acrylamide, a polymerizable molecule, was first modified on the surface of Au NPs for subsequent self-assembly into a monolayer film at the liquid?liquid interface. Through photopolymerization of acrylamide, a chemically cross-linked film was formed with closely
packed nanoparticles, highly macroscopic uniformity, and excellent free-standing property, which allowed it to be easily transferred from the air?water interface onto various solid substrates while maintaining its integrity. It is interesting to find that the macroscopic film underwent an in situ shrinkage under irradiation of UV-light, and its area shrinkage ratio is close to 55% (equal to 2.2 times) of that from non-cross-linked counterparts. More importantly, UV-light-controlled in situ shrinkage of the Au NP film would lead to intelligently, precisely tuned nanogaps less than 0.5 nm between neighboring Au NPs for maximal
amplification of SERS signals, and the macroscopic uniformity of the films ensured the reproducible performance of SERS signals, providing an ideal candidate for SERS applications.