Photoluminescent properties of colloidal quantum dots
Lecturer, Faculty of Engineering
University of Chihuahua
Thursday, March 29, 2018
Abstract: Colloidal quantum dots (CQDs) are a promising material for novel light sources and solar energy conversion. However, trap states associated with the CQD surface can produce non-radiative charge recombination that significantly reduces device performance. Exciton dynamics and interactions in type II colloidal dots (CQDs) with zinc blende structure were investigated by time-resolved. The exciton-exciton interaction energy for CdSe, CdSe/CdTe and CdSe/CdTe/CdS CQDs was investigated using time-resolved PL (TRPL) and compared with transient absorption (TA). The single exciton recombination dynamics were studied by using a theoretically-calculated as a fitting parameter. Combined rate of the non-radiative process was consistent with the localization of holes into shallow traps by an Auger-mediated process. Also, a Chloride passivation of CdTe resulted in a near-complete suppression of the surface traps, producing a significant enhancement of the optical properties.