Calculating the influence of external charges on the photoluminescence of a CdSe quantum dot

The influence of external charges on the radiative recombination rate of an electron-hole pair in a CdSe quantum dot is investigated via atomistic emp irical pseudopotential calculations. It is found that, when a negative exte rnal charge is near the surface of a CdSe quantum dot, its Coulomb potentia l could be strong enough to pull the hole away from the electron and result s in a reduction of the radiative recombination rate by a factor of 70. Dis tance, direction, charge number, and charge type dependences of this effect are investigated.