A microscopic picture of surface charge trapping in semiconductor nanocrystals

J Chem Phys. 2013 May 28;138(20):204705. doi: 10.1063/1.4807054.

Abstract

Several different compositions of semiconductor nanocrystals are subjected to numerous spectroscopic techniques to elucidate the nature of surface trapping in these systems. We find a consistent temperature-dependent relationship between core and surface photoluminescence intensity and marked differences in electron-phonon coupling for core and surface states based on ultrafast measurements and Resonance Raman studies, respectively. These results support a minimal model of surface charge trapping applicable to a range of nanocrystal systems involving a single surface state in which the trapped charge polarization leads to strong phonon couplings, with transitions between the surface and band edge excitonic states being governed by semiclassical electron-transfer theory.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Luminescence
  • Microscopy
  • Nanoparticles / chemistry*
  • Semiconductors
  • Spectrum Analysis, Raman
  • Surface Properties
  • Temperature