Single-particle spectroscopy of doped nanocrystals at room temperature. Te:CdSe

The photoluminescence spectra from single Te-doped CdSe (≈6 nm in diameter, passivated by ZnS) measured at room temperature was analyzed in comparison with those from undoped one. No difference was observed in the emission widths of individual particles of doped and undoped samples, though emissions from doped samples had wider ensemble bands due to an increased inhomogeneity by doping. By successive measurements several dopant emissions showed irreversible blue shifts, which significantly exceeded those observed for the undoped ones. The shifts are ascribed to instability of the dopant in a nanocrystal upon excitation.