Abstract

The Molecular Sciences and Chemistry in particular are at a stage where the properties of molecular materials and interfaces can be custom-designed to encode new properties and function. This includes precision engineering of molecule/electrode interactions in tunnelling junctions, the exploitation of quantum interference effects for new electronic and thermoelectric materials, and the application of spin-polarised surfaces to affect (electro)chemical reactions. Taken together, the notion a ‘Molecular’ Quantum Technology is beginning to emerge. In my talk, I will give an overview of our work around this theme with particular focus on two topics, namely ‘sequencing by tunnelling’ and single-molecule thermoelectrics. Sequencing-by-tunnelling means that the identity of each base in the DNA strand is determined via its quantum-mechanical tunnelling conductance, as a potentially disruptive new way of sequencing DNA , RNA and other biopolymers¹. While the challenges are significant, we and others have made significant progress towards this goal, using an interdisciplinary, ‘whole system’ approach, including interface design, nanofabrication [2,3]. advanced data analysis/Deep Learning [4,5] and electronics [6] The second topic covers some of our work on single-molecule thermoelectrics with particular focus on the thermopower. The latter depends on the slope of the electronic transmission function, which can in turn be tailored by molecular design. I will give examples based on a number of molecular systems we have studied so far and show how the sign and magnitude of the thermopower can provide detailed insight into the energetics of a single-molecule junction. Briefly, I will touch upon first steps towards thin-film devices [7].

[1] T. Albrecht, “Electrochemical Tunnelling Sensors and Their Application”, Nat. Comm. 2012, 3, art. no. 829; [2] AP Ivanov et al., “DNA Tunnelling Detector Embedded in a Nanopore”, Nano Lett. 2011, 11, 279-285; [3] AP Ivanov et al., “High Precision Fabrication and Positioning of Nanoelectrodes in a Nanopore”, ACS Nano 2014, 8, 1940-1948; [4] M Lemmer et al., “Unsupervised Vector-based Classification of Single-Molecule Charge Transport Data”, Nat. Comm. 2016, 7, art. no. 12922; [5] T. Albrecht et al., “Deep Learning for Single-Molecule Science”, Nanotechnology 2017, 28, art. no. 423001 (tutorial); [6] M Carminati et al., “Design and Characterisation of a Current Sensing Platform for Silicon-based Nanopores with Integrated Tunnelling Nanoelectrodes”, Anal. Integr. Circ. Sign. Proc. 2013, 77, 333-343; [7] B. Li et al., “Cross-plane Conductance through a Graphene/Molecular Monolayer/Au Sandwich”, Nanoscale 2018, 10, 19791-19798.