Photoluminescence spectroscopy of PbSe nanocrystals

The low-energy electronic states of PbSe quantum dots are investigated using photoluminescence spectroscopies. Size-selective photoluminescence measurements produce unexpectedly broad (similar to 50 meV) emission lines. In addition, significant anti-Stokes luminescence is observed. Finally, we observe a size-dependent splitting of the lowest emission feature. Possible origins of the broad emission lines observed despite size-selective excitation and the splitting of the emission spectrum will be discussed.