We report a study of the influence of high intensity laser light on the optical properties and exciton relaxation dynamics in CdSe nanocrystals passivated by tri- n -octylphosphine oxide and dispersed in the optically clear poly(butylmethacrylate) polymer. Sample irradiation by 3 ps duration laser pulses at 527 nm leads to the blueshift of the maximum of the lowest-energy exciton absorption band and to the disappearance of a long-wavelength absorption slope in the 600-800 nm region that we attribute to Rayleigh scattering. The photomodification rate is approximately proportional to the second to third power of the light intensity and strongly temperature dependent. The shift of the absorption band is related to the reduction of the nanocrystal (NC) size. The disappearance of the Rayleigh scatter is explained as a modification of the NC surface ligands and their immediate surroundings due to an increase in the local temperature.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)