Temperature dependence of the band gap of colloidal CdSe/ZnS core/shell nanocrystals embedded into an ultraviolet curable resin

Optical absorption and photoluminescence techniques were used to investigate the energy band gap of CdSe/ZnS core/shell nanocrystals matrixed into a resin. The band gap is measured as a function of temperature for several samples with different nanocrystal diameters. Debye and Einstein temperatures were obtained by fitting the energy band gap using two different empirical expressions. Stokes shift was estimated by taking the difference between the first exciton and emission peaks. The Stokes shift was found to increase as the nanocrystal diameter is decreased suggesting a stronger electron-phonon coupling in smaller size nanocrystals. (c) 2006 American Institute of Physics.