Photoinduced Interfacial Charging and “Explosion” of Monolayer Pentacene Islands

  • Chemistry
  • Physics
  • R&D
  • Technology
  • Alex K. Shalek
  • Chen L. et al.▾
    Chen L., Cherniavskaya, O., Shalek, A.K., and Brus, L.
  • Nano Lett , Volume 5 , Issue 2241
  • November, 2005
Chemistry
Physics
R&D
Technology
Alex K. Shalek

Abstract

Abstract

Electrostatic force microscopy shows that the electric field gradients above pentacene monolayer islands on 2-nm SiO2/Si substrates, in a dark, dry nitrogen environment, display a wide distribution of signs and magnitude that is dependent on sample history. Under 12 mW/cm2 green (532 nm) illumination, pentacene islands accumulate positive charge because of photoexcited electron transfer across the oxide to the Si substrate. At a strong illumination of 60 mW/cm2, pentacene islands reform into small spherical particles, apparently because the positive charge Coulomb repulsion energy becomes comparable to the cohesive energy of the pentacene monolayer.

Photoinduced Interfacial Charging and “Explosion” of Monolayer Pentacene Islands