Revisiting the Anion Framework Conservation in Cation Exchange Processes

High Resolution Image Download MS PowerPoint Slide We investigated the effect of cation exchange on the anionic framework of lightly doped CdSe:Te/CdS nanorods. In contrast with previously studied core/shell systems, the Te dopant, located in the center of the CdSe core, provides an extremely sensitive indicator for any structural changes of the anionic framework that may occur as a result of the cation exchange process. We first optimized the cation exchange procedure in order to retain the fluorescence properties of the CdSe:Te/CdS nanorods after exchange of Cd 2+ for Cu + and back to Cd 2+ . Next, using multiexciton spectroscopy, we were able to probe the magnitude of the exciton–exciton repulsion interaction and use that to assess the degree of crystal structure conservation. Our findings provide a much stronger proof that the anion framework is indeed rigid, showing no evidence of significant migration of the anionic dopant.