Electroabsorption spectra of PbSe nanocrystal quantum dots

The quantum-confined Stark effect of PbSe nanocrystal quantum dots (QDs) in a polymer film has been studied for the near-infrared absorption in the region of 1300-1600 nm (corresponding to diameters of 4.0-7.0 nm) by using electric field modulation spectroscopy. Electroabsorption spectra of QDs show the electric-field-induced energy shift in the exciton state, resulting in the spectral broadening given by the second derivative of the absorption spectra. It is shown that the magnitude of the change in electric dipole moment following excitation into the first exciton state increases with an increase in the size of QDs. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3583450]