Hybrid exciton state in a quantum dot–dendrite system: Green functions

Abstract

A model is proposed to study the hybrid exciton in a quantum dotdendrimer systems. The semiconductor organic hybrid exciton is studied using a "real space" Green's function method and a diagrammatic technique. The energy of the hybrid exciton as well as the Green function matrix elements have been calculated for different quantum dot-dendrimer systems, and the method can be applied for systems with different structures. Using the double-time Green's functions the optical processes can be calculated. The optical properties of the systems are controllable by the size and structure of the QD-dendrimer systems.

Wannier–Frenkel hybrid exciton in organic–semiconductor quantum dot heterostructures

“…The details of the method and calculation can be found in Ref. [6]. In this diagram technique every site corresponds to a graph vertex.…”

“…The interaction between molecules in the same chain causes this effective interaction between dendrimer generations, which is calculated in Ref. [6].…”

“…To realize this idea, physicists recently proposed different systems with different geometrical configuration of organic-semiconductor heterostructures so that a new type of hybrid exciton can be formed [1][2][3][4][5][6]. Due to dipole-dipole interaction at the interface, hybrid excitons are formed at a junction or boundary between semiconductor and organic materials and the mixture of the two states is enhanced if the respective energy levels are in or near resonance.…”

“…The resonance coupling of Frenkel excitons in the medium and Wannier excitons in the dot array is determined by the interaction Hamiltonian taken similarly to Ref. [6]:…”

Optical properties of P3HT:tributylphosphine oxide-capped CdSe nanocomposites

“…These hybrid excitons have the & A. Benchaabane benchaabane.aida@yahoo.fr 1 Laboratoire de Physique de la Matière Condensée, Faculté des Sciences d'Amiens, 80039 Amiens, France best properties of both Frenkel and Wannier excitons and are very sensitive to external electric and magnetic field perturbation. Moreover, they can present large optical resonance nonlinearity and low excitons saturation density [13][14][15], which is supposed to improve the optoelectronic properties of the sample with an enhancement of photogeneration carriers. The combination of these two constituents contributes to better optoelectronic properties in terms of high refractive index and permittivity [16].…”