Extremely Slow Spontaneous Electron Trapping in Photodoped -Type CdSe Nanocrystals.

The trapping dynamics of conduction-band electrons in colloidal degenerately doped -CdSe nanocrystals prepared by photochemical reduction (photodoping) were measured by direct optical methods. The nanocrystals show spontaneous electron trapping with distributed kinetics that extend to remarkably long timescales. Shifts in nanocrystal band-edge potentials caused by quantum confinement and surface ion stoichiometry were also measured by spectroelectrochemical techniques, and their relationship to the slow electron trapping is discussed.