Publication Details (including relevant citation information):
van Zijll, Marshall, Borders, Bryan, Mazur, Ursula, Hipps, K. W. The Journal of Physical Chemistry C 2016 120 (27) 14962-14968
Abstract: Persistent conductivity is observed following Ar+ bombardment of meso-tetra(4-pyridyl)porphyrin:meso-tetra(4-sulfonatophenyl)porphyrin (TPyP:TSPP) nanorods. The lifetime of the persistent conductivity in ultrahigh vacuum (UHV) is exceptionally long at room temperature, between 106 and 107 s. Ion beam currents can be used to both increase and decrease the level of persistent conductivity in these nanorods. Initial Ar+ bombardment of a sample causes an increase in the persistent current. Subsequent bombardment with low-energy Ar+ can cause a rapid decrease in the persistent current. A model is presented which presumes that persistent conductivity is carried by metastable defects with rates of excitation and relaxation following the Arrhenius relationship. Energy conservation suggests that ion bombardment introduces a thermal gradient across the nanorod which quickly quenches when ion bombardment ceases. This quick quenching results in a population of metastable defects which decay very slowly at room temperature.
Address (URL): http://dx.doi.org/10.1021/acs.jpcc.6b04689