Enhanced optical nonlinearity of hybrid excitons in an inorganic semiconducting quantum dot covered by an organic layer

We study excited states in an inorganic semiconducting quantum dot that is covered by a thin organic layer. The resonant energy transfer due to dipole-dipole interaction leads to the appearance of new states, mixed Wannier-Mott and Frenkel excitons (hybrid excitons). These new states have quite remarkable properties such as large optical nonlinearities and short lifetimes, which should be especially interesting with respect to applications in nonlinear optics. The parameter, governing the strength of the coupling between the two excitonic states, depends on the size of the system and can, therefore, be controlled experimentally.