Quantum dot lattice embedded in an organic medium: Hybrid exciton state and optical response

[摘要] We propose a model to implement organic exciton-semiconductor exciton hybridization by embedding a semiconductor quantum dot array into an organic medium. A Wannier-Mott transfer exciton is formed when the exciton in each semiconductor dot interacts via multipole-multipole coupling with other excitons in the different dots of the array. A hybrid exciton appears in the system owing to strong dipole-dipole interaction of the Frenkel exciton of the organic molecules with the Wannier-Mott transfer exciton of the quantum dot array. This hybrid exciton has both a large oscillator strength (Frenkel-like) and a large exciton Bohr radius (Wannier-like). At resonance between these two types of excitons, the optical nonlinearity is very high and can be controlled by changing parameters of the system such as dot radius and dot spacing.

[关键词] SEMICONDUCTOR MICROCRYSTALLITES;NONLINEARITY;LUMINESCENCE