Shell layer dependence of photoblinking in CdSe/ZnSe/ZnS quantum dots

Abstract

We report on the influence of shell addition, shell thickness, and shape of CdSe/ZnSe/ZnS colloidal quantum dots (QDs) on luminescence, decay lifetime, and photoblinking. The addition of shell layers appreciably increased (decreased) the time interval of on (off) time, while the increase of outer shell thickness only increases the time interval of on-time. The photoblinking was suppressed as the QD shape changes from spherical to ellipsoidal probably due to the reduction of Auger process as the wave function degeneracy of the identical states of the two holes is lifted. We also suggest that interface traps might enhance the Auger recombination. (C) 2011 American Institute of Physics. [doi:10.1063/1.3533401]