  We theoretically study the effect of the dielectric environment on the
exciton ground state of CdSe and CdTe/CdSe/CdTe nanorods. We show that
insulating environments enhance the exciton recombination rate and blueshift
the emission peak by tens of meV. These effects are particularly pronounced for
type-II nanorods. In these structures, the dielectric confinement may even
modify the spatial distribution of electron and hole charges. A critical
electric field is required to separate electrons from holes, whose value
increases with the insulating strength of the surroundings.
