Features of luminescence of colloidal quantum dot clusters

Abstract

Salient features of luminescence of colloidal quantum dot (QD) nanoclusters (NC) determined by nonradiative transfer of electronic excitation energy within the NC are discussed. It is shown that the NC luminescence spectrum changed significantly in comparison with the spectrum of the colloid solution, in which formation of NC occurred, provided sufficiently strong interaction between the QDs. The luminescence spectrum of the initial QD colloid solution has inhomogeneous broadening determined by the finite dispersion of the QD size distribution and quantum size effects, i.e. by the dependence of the luminescence peak position of the individual QD on its size. Bathochromic shift of the luminescence spectrum occurs on the NC formation due to the energy transfer from the smaller size QD to the larger size QD, and as a result, the luminescence lifetime in the short-wavelength region decreases.