Date: 13.01.2023, Time: 15:30h

Location: Kleiner Physik-Hörsaal N 020, Fakultät für Physik
The talk will be streamed online.

Jussi Toppari
Nanoscience Center and Department of Physics, University of Jyväskylä, Finland

The molecular electronics as well as molecular scale optics, i.e. plasmonics, have long been visualized to pose the next big leap in technology development. At a moment, DNA has proven to be one of the most versatile and promising molecule for nanoscale fabrication due to its outstanding self-assembly possibilities [1], especially for electrical and plasmonic purposes [2]. Because the self-assembly happens in a fully parallel manner, one can simultaneously fabricate huge amounts of devices. However, since this happens usually in solution, one needs a way to combine these bottom-up methods with some top-down method to - in the simplest case - position the assembled devices. Yet, combining the self-assembly directly with top-down methods during the fabrication, can yield even more versatile fabrication methods.

We have developed methods to trap and connect single molecular scale devices with other electrical circuitry [2,3], and utilized this to study the conductance of several types of individual DNA nanostructures. For nanoscale optics, we have developed a novel DNA-assisted lithography (DALI) method, which takes advantage of the DNA origami constructions and together with conventional top-down nanofabrication processes enables fabrication of high-quality sub-100-nanometer plasmonic nanostructures with desired shapes [4]. As a demonstration, we have fabricated optical bowtie antennas with a tunable plasmonic resonance in visible range. The method enables also fabrication of large optically chiral surfaces with high coverage.

To obtain the best possible optical response, we are expanding the DALI method to organized large lattices of DNA-origami and fabricating metallic metamaterials out of that. So far, this kind of lattices have been fabricated mainly on mica [5], which is not compatible with almost any top-down methods. Thus, transporting the methods on silicon will open new avenues for DNA-based fabrication [6]. In addition, we have found a way to fabricate rolled DNA-origami-lattices to form tubular geometries [7].

[1] A.V. Pinheiro, et al. (2011) Nat. Nanotech. 6, 763; M. Madsen, K.V. Gothelf, (2019) Chem. Rev. 119, 6384.
[2] V. Linko, J.J. Toppari (2013) SAME 1, 101; L.N. Liu, T. Liedl (2018) Chem. Rev. 118, 3032.
[3] K. Tapio, J. Leppiniemi, B. Shen, V.P. Hytönen, W. Fritzsche, J.J. Toppari (2016) Nano Lett., 16, 6780.
[4] B. Shen, et al. Nanoscale (2015) 7, 11267; B. Shen, et al. (2018) Science Adv. 4, eaap8978.
[5] J.M. Parikka, K. Sokołowska, N. Markešević and J.J. Toppari (2021) Molecules 26, 1502.
[6] K. Tapio, C. Kielar, J.M. Parikka, A. Keller, H. Järvinen, K. Fahmy, J.J. Toppari (2023) In Review.
[7] J. Parikka, H. Järvinen, K. Sokołowska, V. Ruokolainen, N. Markešević, A. Natarajan, A. Kuzyk, K. Tapio,J.J. Toppari (2023) In Review.