Single DNA Molecular Rectifier Enabled by Structure Modification

Cunlan Guo ¹ Kun Wang ¹ Elinor Zerah-Harush harushel@post.bgu.ac.il ^2,3 Joseph Hamill ¹ Bin Wang ¹ Yonatan Dubi ^2,3 Bingqian Xu ¹

¹Single Molecule Study Laboratory, University of Georgia, Athens
²Chemistry, Ben-Gurion University of the Negev, Beer-Sheva
³Department of Chemistry & Ilse-Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva

The predictability, diversity and programmability of DNA make it a leading candidate for the design of functional electronic devices that use single molecules, yet its electron transport properties have not been fully elucidated. This is primarily because of a poor understanding of how the structure of DNA determines its electron transport. Here, DNA-based molecular rectifier is demostrated constructed by site-specific intercalation of small molecules (coralyne) into a custom-designed 11-base-pair DNA duplex. Measured current–voltage curves of the DNA–coralyne molecular junction show unexpectedly large rectification with a rectification ratio of about 15 at 1.1 V, a counter-intuitive finding considering the seemingly symmetrical molecular structure of the junction. A non-equilibrium Green’s function-based model— parameterized by density functional theory calculations—revealed that the coralyne-induced spatial asymmetry in the electron state distribution caused the observed rectification. This inherent asymmetry leads to changes in the coupling of the molecular HOMO−1 level to the electrodes when an external voltage is applied, resulting in an asymmetric change in transmission.

Cunlan Guo, Kun Wang, Elinor Zerah-Harush, Joseph Hamill, Bin Wang, Yonatan Dubi, Bingqian Xu. Molecular rectifier composed of DNA with high rectification ratio enabled by intercalation. Nature Chemistry 8, 484–490 (2016).