The Redox Chemistry at the Interface for Retrieving and Brightening the Emission of Doped Semiconductor Nanocrystals.

ABSTRACT

Photo-oxidation of semiconductor quantum dots is the prime concern during their processability, as it often induces nonradiative states and quenches the band edge excitonic emission. Nevertheless, similar effects have been observed for light emitting doped semiconductor nanocrystals, and the dopant emissions are also quenched due to the surface oxidation. This is more pronounced for selenide-based host semiconductors. To overcome this, we study the interface chemistry of Cu-doped and Mn-doped ZnSe nanocrystals and report here the retrieving and brightening of the emission from completely quenched months old doped nanocrystals. This has been obtained by treating the doped nanocrystals with appropriate organic thiol ligands which remove the surface oxidative states as well as resist further oxidation of the nanocrystals. Here, we investigate details of the redox chemistry at the interface and study related photophysics in retrieving the dopant emission.