We study light absorption by nearly monodisperse PbS nanocrystals grown in a glass matrix. The absorption spectra demonstrate a well-resolved structure at energies above the first absorption peak. The absorption cross sections are calculated with an empirical tight-binding model accounting for the quantum confinement, the band anisotropy, and valley splittings. Absorption spectra measured at 4 K quantitatively agree with the atomistic calculations. This allows us to unambiguously ascribe the much-debated second absorption peak to the p-p optical transition and directly measure the splitting of excited p states.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films