Jones LO, Mosquera MA, Schatz GC, Ratner MA. Molecular Junctions Inspired by Nature: Electrical Conduction through Noncovalent Nanobelts.
J Phys Chem B 2019;
123:8096-8102. [PMID:
31525929 DOI:
10.1021/acs.jpcb.9b06255]
[Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Charge transport occurs in a range of biomolecular systems, whose structures have covalent and noncovalent bonds. Understanding from these systems have yet to translate into molecular junction devices. We design junctions which have hydrogen-bonds between the edges of a series of prototype noncovalent nanobelts (NCNs) and vary the number of donor-acceptors to study their electrical properties. From frontier molecular orbitals (FMOs) and projected density of state (DOS) calculations, we found these NCN dimer junctions to have low HOMO-LUMO gaps and states at the Fermi level, suggesting these are metallic-like systems. Their conductance properties were studied with nonequilibrium Green's functions density functional theory (NEGF-DFT) and was found to decrease with cooperative H-bonding, that is, the conductance decreased as the alternating donor-acceptors around the nanobelts attenuates to a uniform distribution in the H-bonding arrays. The latter gave the highest conductance of 51.3 × 10-6 S and the Seebeck coefficient showed n-type (-36 to -39 μV K-1) behavior, while the lower conductors with alternating H-bonds are p-type (49.7 to 204 μV K-1). In addition, the NCNs have appreciable binding energies (19.8 to 46.1 kcal mol-1), implying they could form self-assembled monolayer (SAM) heterojunctions leading to a polymeric network for long-range charge transport.
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