Direct Chemical Synthesis of Plasmonic Black Colloidal Gold Superparticles with Broadband Absorption Properties.

Kwon, Nayoung; Oh, Hwisu; Kim, Reehyang; Sinha, Arjyabaran; Kim, Jaeyun; Shin, Jonghwa; Chon, James W M; Lim, Byungkwon · Nano Lett · 2018

basic_science · Level V

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Abstract

Self-assembly of plasmonic metal nanoparticles can provide an opportunity of creating colloidal superparticles with fascinating optical properties arising from interparticle plasmonic coupling, but typically requires multiple steps involving solvent and/or ligand exchange. We developed a direct, one-step chemical synthesis of plasmonic black colloidal Au superparticles with broadband absorption in visible and near-infrared regions. During the synthesis, the Au superparticles were formed through self-assembly of in-situ-formed Au nanoparticles driven by solvophobic interactions between nanoparticles and solvent. These superparticles could be solution-processed to fabricate a thin film, which exhibited near-perfect absorption over a broad range from 400 nm to 2.5 μm as well as the excellent antireflective property. Thanks to their broadband absorption property, the Au superparticles showed good performances for near-infrared surface-enhanced Raman spectroscopy and light-to-heat conversion.