Polypeptides in alpha-helix conformation perform as diodes. Academic Article uri icon


  • Molecules that resemble a semiconductor diode depletion zone are those with an intrinsic electric dipole, which were suggested as potential electronic devices. However, so far, no single molecule has met such a goal because any electron donor-acceptor linker strongly diminishes any possibility of diode behavior. We find an intrinsic diode behavior in polypeptides such as poly(L-alanine) and polyglycine in alpha-helix conformation, explained in terms of molecular orbital theory using ab initio methods. The application of an antiparallel electric field with respect to the molecular dipole yields a gradual increase in current through the junction because the valence and conduction orbitals approach each other reducing their gap as the bias increases. However, a parallel field makes the gap energy increase, avoiding the pass of the electrons.

published proceedings

  • J Chem Phys

author list (cited authors)

  • Cristancho, D., & Seminario, J. M.

citation count

  • 33

complete list of authors

  • Cristancho, Dahiyana||Seminario, Jorge M

publication date

  • February 2010