Plasmonic nanocrystals, which exhibit extraordinary optical properties, are challenging to grow in selective positions with a cost-effective and high-throughput process. We demonstrate that plasmonic isotropic gold nanospheres (AuNSs) can be selectively synthesized on wafer-scale rigid and flexible substrates at room temperature by laser irradiation. First, we prepare gold nanocolumn (AuNC) thin films on sapphire and polydimethylsiloxane substrates with glancing angle deposition (GAD). Then, a KrF excimer laser is exposed at selected positions with a 24 ns pulse duration. Finally, highly isotropic AuNSs as plasmonic nanocrystals are synthesized at the targeted positions. We suggest that the formation of such isotropic AuNSs is caused by reshaping from the top of the AuNCs; this is verified by the temperature distribution in the AuNCs during laser irradiation through finite element method simulations. We further investigate the formation of AuNSs by varying the laser energy density and the kind of substrate. By using a simple mask process, we demonstrate patterning of the letters "KIST" via selectively grown AuNSs on a flexible substrate. The simple laser irradiation process on GAD-grown metal NC thin films is expected to be a promising method for scalable synthesis of plasmonic isotropic NSs at targeted positions with a rapid process and at room temperature.
Bibliographical noteFunding Information:
This work was supported by the Institute for Information & Communications Technology Promotion (IITP) grant (No. R0126-16-1050), by the Basic Research Laboratory Program (2016R1A4A1012950), and by Fundamental Technology Research Program (2014M3A7B4052202 and 2015M3C1A3002152) through the National Research Foundation of Korea (NRF) grant funded by the Ministry of Science, ICT and Future Planning (MSIP). Also, this work was financially supported by the Institutional Research Program of the Korea Institute of Science and Technology (2E28210) and KU-KIST Graduate School of Converging Science and Technology Program.
© 2018 The Royal Society of Chemistry.
ASJC Scopus subject areas
- General Chemistry
- Materials Chemistry