Owing to plasmonic resonances, metallic nanostructures have unique optical properties such as high local field enhancement and subwavelength confinement of light, which e.g. provide enhanced fluorescence [1] and enable Raman spectroscopy even from a single molecule [2]. Recently, plasmonic nanostructures have been also utilized in quantum photonics [3] and as components of novel metamaterials [4–6] which have proven to possess novel electromagnetic properties enabling breakthrough applications [7]. In health and biosciences, plasmonics has been widely used for sensing and diagnostics [8–11]. Especially chiral nanoparticles and metamaterials have been an emerging hot topic due to their potential for novel enantiomer sensitive detection [12,13].
Since the plasmonic resonances are dramatically affected by the material, size and shape of the metal nanostructure, above purposes demand precise control of nanostructure morphology. Despite truly impressive progress in the field of plasmonics enabled by advanced nanofabrication techniques, creating complex and sufficiently small metallic shapes for metamaterials operating at the visible wavelength range remains challenging. Top-down lithography based nanofabrication relies on the use of slow and expensive equipment, and even state-of-the-art systems have limited spatial accuracy (~10 nm). On the other hand, the common bottom-up wet chemical methods yield tiny but geometrically limited nanoparticles with morphologies usually dictated by the crystalline structures of materials. Thus, development of methods allowing cost effective large-scale fabrication of metal nanostructures of complex shapes with nanoscale accuracy, is of great importance for further advancement of nanophotonics and development of real life applications.

The project is funded by the Aufbaubank Thüringen -Verbund under the number 2018 VF 0015; 2018 FE 9039.