Mediating ordered assembly of gold nanorods by controlling droplet evaporation modes for surface enhanced Raman scattering

The evaporation induced self-assembly of nanomaterials has emerged as one of the important approaches to fabricate various ordered nanostructures with enhanced optical properties. In this study, gold nanorods (GNRs) were selected as a building block and investigated for the droplet evaporation induced self-assembly of GNRs by using self-assembled monolayers (SAMs) as a tool to control droplet evaporation mode. By controlling the droplet evaporation mode of colloidal GNRs, the large scale ordered assemblies of GNRs were successfully fabricated with significantly enhanced collective optical properties such as two photon luminescence (TPL) and surface enhanced Raman scattering (SERS). The confined ordered assembly of GNRs was also achieved on a pre-designated region through the combination of surface-mediated droplet evaporation with soft lithography and/or mass spectrometry assisted lithography.