title: A Chemical Approach To Break the Planar Configuration of Ag Nanocubes into Tunable Two-Dimensional Metasurfaces.
abstract: Current plasmonic metasurfaces of nanocubes are limited to planar configurations, restricting the ability to create tailored local electromagnetic fields. Here, we report a new chemical strategy to achieve tunable metasurfaces with nonplanar nanocube orientations, creating novel lattice-dependent field localization patterns. We manipulate the interfacial behaviors of Ag nanocubes by controlling the ratio of hydrophilic/hydrophobic molecules added in a binary thiol mixture during the surface functionalization step. The nanocube orientation at an oil/water interface can consequently be continuously tuned from planar to tilted and standing configurations, leading to the organization of Ag nanocubes into three unique large-area metacrystals, including square close-packed, linear, and hexagonal lattices. In particular, the linear and hexagonal metacrystals are unusual open lattices comprising nonplanar nanocubes, creating unique local electromagnetic field distribution patterns. Large-area "hot hexagons" with significant delocalization of hot spots form in the hexagonal metacrystal. With a lowest packing density of 24%, the hexagonal metacrystal generates nearly 350-fold stronger surface-enhanced Raman scattering as compared to the other denser-packing metacrystals, demonstrating the importance of achieving control over the geometrical and spatial orientation of the nanocubes in the metacrystals.
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371.
authors.forename: Yijie
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371.
authors.forename: Yih Hong
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research) , 2 Fusionopolis Way, Innovis, 08-03, Singapore 138634.
authors.forename: In Yee
authors.initials: IY
authors.lastname: Phang
authors.affiliation: Department of Physics, The Chinese University of Hong Kong , Shatin, Hong Kong, China.|School of Materials Science and Engineering, Shaanxi Normal University , Xi'an 710119, Shaanxi, China.
authors.forename: Ruibin
authors.initials: R
authors.lastname: Jiang
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371.
authors.forename: Howard Yi Fan
authors.initials: HY
authors.lastname: Sim
authors.affiliation: Department of Physics, The Chinese University of Hong Kong , Shatin, Hong Kong, China.
authors.forename: Jianfang
authors.initials: J
authors.lastname: Wang
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371.
authors.forename: Xing Yi
authors.initials: XY
authors.lastname: Ling
keywords: Ag nanocube; Surface chemistry; hot spot tailoring; mixed monolayer; surface-enhanced Raman scattering (SERS); tunable metasurfaces