Laser induced luminescence of dense films of CdSe/ZnS nanoparticles

Optical properties of the films with high concentration of semiconductor core-shell CdSe/ZnS nanocrystals under action of visible laser radiation in a wide range of power densities have been investigated. It's shown that in the films with ultimate concentration of the nanocrystals a quantum-size effect is observed. High concentration of the nanocrystals in the films and the presence of dipoles caused by nanoparticles asymmetry lead to strong shift of quantum-size peaks in absorption and luminescence spectra compared to the solution and the films with low concentration of the nanoparticles. The altitude of the shift depends on the thickness of the films and varies from 35 nm to 50 nm. The luminescence spectra of the films don't change until the power density of exciting laser radiation exceeds 1.10(6) W/cm(2). The regimes of laser action on the films of the nanoparticles with power densities beyond the threshold of films destruction (from 5(.)10(6) W/cm(2) to 1.10(9) W/cm(2)) have been investigated.