Unimolecular rectifier

Hydrogen can be removed from individual H2TPP molecules by applying excess voltage to the tip of a scanning tunneling microscope (STAM, a); this removal alters the current-voltage (I-V) curves of TPP molecules, measured using the same STM tip, from diode-like (red curve in b) to resistor-like (green curve). Image (c) shows a row of TPP, H2TPP and TPP molecules. While scanning image (d), excess voltage was applied to H2TPP at the black dot, which instantly removed hydrogen, as shown in the bottom part of (d) and in the re-scan image (e).[1]

A unimolecular rectifier is a single organic molecule which functions as a rectifier (one-way conductor) of electric current. The idea was first proposed in 1974 by Arieh (later Ari) Aviram, then at IBM, and Mark Ratner, then at New York University.[2] Their publication was the first serious and concrete theoretical proposal in the new field of molecular electronics (UE). Based on the mesomeric effect of certain chemical compounds on organic molecules, a molecular rectifier was built by simulating the pn junction with the help of chemical compounds.

Their proposed rectifying molecule was designed so that electrical conduction within it would be favored from the electron-rich subunit or moiety (electron donor) to an electron-poor moiety (electron acceptor), but disfavored (by several electron volts) in the reverse direction.

  1. ^ Zoldan, Vinícius Claudio; Faccio, Ricardo & Pasa, André Avelino (2015). "N and p type character of single molecule diodes". Scientific Reports. 5: 8350. doi:10.1038/srep08350. PMC 4322354. PMID 25666850.
  2. ^ Aviram, Arieh; Ratner, Mark A. (1974). "Molecular rectifiers". Chemical Physics Letters. 29 (2): 277. Bibcode:1974CPL....29..277A. doi:10.1016/0009-2614(74)85031-1.