PbS quantum dot electroabsorption modulation across the extended communications band 1200-1700 nm

We report electric field-induced modulation of absorption in PbS nanocrystal quantum dots across the spectral region 600-2000 nm, encompassing the entire telecommunications band. The maxima in the electroabsorption spectra correspond with the positions of the first excitonic peak, confirming the predominance of excitonic broadening as the basis for the observed effect. We estimate the change in dipole moment to be on the order of 20 D in 7 nm diameter PbS nanocrystals compared to previously-reported similar to 100 D in CdSe. (c) 2005 American Institute of Physics.