Spin-polarizable excitonic luminescence in colloidal mn ²⁺-doped CdSe quantum dots

The photoluminescence of colloidal Mn ²⁺-doped CdSe nanocrystals has been studied as a function of nanocrystal diameter. These nanocrystals are shown to be unique among colloidal doped semiconductor nanocrystals reported to date in that quantum confinement allows tuning of the CdSe bandgap energy across the Mn ²⁺ excited-state energies. At small diameters, the nanocrystal photoluminescence is dominated by Mn ²⁺ emission. At large diameters, CdSe excitonic photoluminescence dominates. The latter scenario has allowed spin-polarized excitonic photoluminescence to be observed in colloidal doped semiconductor nanocrystals for the first time.