Shape dependence of resonant energy transfer between semiconductor nanocrystals

We theoretically study the energy transfer between semiconductor nanocrystal dots and rods of CdSe using a semiempirical pseudopotential method (SEPM) description of the electronic structure of the nanocrystals, followed by evaluation of the Coulombic contribution to the energy transfer evaluated using the transition density cube (TDC) method. Our results are compared to the dipole-dipole theory of Forster to characterize the effects of nanocrystal shape, distance, and orientation. For the distances typical of nanorod solids, we find that the dipole-dipole theory underestimates the coupling between linearly oriented nanorods by as much as a factor of 2, and overestimates the coupling between parallel nanorods by as much as a factor of 3.