Direct Assembly of Vertically Oriented, Gold Nanorod Arrays. (29th October 2020)

• Record Type: Journal Article
• Authors: Zhang, Heyou; Liu, Yawei; Shahidan, Muhammad Faris Shahin; Kinnear, Calum; Maasoumi, Fatemeh; Cadusch, Jasper; Akinoglu, Eser Metin; James, Timothy D.; Widmer‐Cooper, Asaph; Roberts, Ann; Mulvaney, Paul
• Is Part Of: Advanced functional materials. Volume 31:Number 6(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-29
• Subjects: arrays -- assembly -- electric field induced dipole -- electrophoretic deposition -- gold nanorods -- plasmonic -- vertical orientation; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202006753
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Although many nanoscale materials such as quantum dots and metallic nanocrystals exhibit size dependent optical properties, it has been difficult to incorporate them into optical or electronic devices because there are currently no methods for precise, large‐scale deposition of single nanocrystals. Of particular interest is the need to control the orientation of single nanocrystals since the optical properties are usually strongly anisotropic. Here a method based on electrophoretic deposition (EPD) is reported to precisely assemble vertically oriented, single gold nanorods. It is demonstrated that the orientation of gold nanorods during deposition is controlled by the electric dipole moment induced along the rod by the electric field. Dissipative particle dynamics simulations indicate that the magnitude of this dipole moment is dominated by the polarizability of the solution phase electric double layer around the nanorod. The resulting vertical gold nanorod arrays exhibit reflected colors due to selective excitation of the transverse surface plasmon mode. The EPD method allows assembly of arrays with a density of over one million, visually resolvable, vertical nanorods per square millimeter. Abstract : Electrophoretic deposition of nanocrystals can be used to fabricate arrays of single, vertically oriented, gold nanorods. The orientation is controlled by the applied electric field, rod aspect ratio, and electrolyte composition. The resultant arrays can be used to create tunable optical filters.