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

Huong, Nguyen Que; Birman, Joseph L.

doi:10.1103/physrevb.61.13131

Cited by 20 publications

(19 citation statements)

References 17 publications

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“…Written in terms of the creation and annihilation operators, Hamiltonian [6] is given by is the creation (annihilation) operator for Frenkel exciton. For a spherical quantum dot, the oscillator strength is concentrated mainly on the first lowest states.…”

Section: Mathematical Expressionsmentioning

confidence: 99%

Engineered nanostructures exhibiting enhanced optical nonlinearity

Potasek

2009

SPIE Proceedings

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Because of their unique chemical and physical properties, nanometer-sized semiconductor materials have attracted broad attention in the fields of physics, chemistry, and biology. These capabilities are mainly due to the unusual dependence of the electronic and optical properties on quantum confinement, which for semiconductor materials restricts the particle size in the 1 to 10 nm range. We have fabricated and measured novel nanostructures of semiconductor quantum dots capped with surfactants and embedded in organic thin films that exhibit several orders of magnitude increase in their multiphoton cross-sections of absorption relative to semiconductor quantum dots capped with surfactants in solution or in other matrix materials. Large values of optical nonlinearity have been measured for CdS and CdSe quantum dots in these engineered nanostructures. We will discuss these findings within the context of theoretically proposed hybrid excitons in organic-inorganic nanostructures.

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Section: Mathematical Expressionsmentioning

confidence: 99%

Engineered nanostructures exhibiting enhanced optical nonlinearity

Potasek

2009

SPIE Proceedings

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“…Other realizations for the hybrid have been proposed. Examples are hybrid excitons in an inorganic semi-conducting quantum dot covered by an organic layer 3 and quantum dot-dendrimer system 4 . The energy of the hybrid exciton as well as the Green's function matrix elements for different quantum dot-dendrimer systems has been calculated.…”

Section: Introductionmentioning

confidence: 99%

Hybridized quadrupole-dipole exciton effects in aCu2O-organic heterostructure

Roslyak

Birman²

2007

Phys. Rev. B

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In the present work we discuss resonant hybridization of the 1S quadrupole Wannier-Mott exciton (WE) in a Cu2O quantum well with the Frenkel (FE) dipole exciton in an adjacent layer of organic DCM2:CA:PA. The coupling between excitons is due to interaction between the gradient of electric field induced by DCM2 Frenkel exciton and the quadrupole moment of the 1S transition in the cuprous oxide. The specific choice of the organic allows us to use the mechanism of 'solid state solvation' (Bulovic 1 ) to dynamically tune the WE and FE into resonance during time ≈ 3.3ns (comparable with the big life time of the WE) of the 'slow' phase of the solvation. The quadrupole-dipole hybrid utilizes the big oscillator strength of the FE along with the big lifetime of the quadrupole exciton, unlike dipole-dipole hybrid exciton which utilizes big oscillator strength of the FE and big radius of the dipole allowed WE. Due to strong spatial dispersion and big mass of the quadrupole WE the hybridization is not masked by the kinetic energy or the radiative broadening. The lower branch of the hybrid dispersion exhibits a pronounced minimum and may be used in applications. Also we investigate and report noticeable change in the coupling due to a induced 'Stark effect' from the strong local electric field of the FE. We investigated the fine energy structure of the quantum well confined ortho and para excitons in cuprous oxide.

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“…Then one can expect to have an hybrid exciton with very strong oscillator strength as well as very large exciton radius. Several specific systems of this semiconductororganic combination were proposed [9][10][11][12] such as a neighboring structure of organic and semiconductor quantum wells [9], neighboring organic and inorganic quantum wires [10], a single quantum dot in an organic shell [11] and the system of quantum dot array embedded in an organic host [12]. The obtained hybrid exciton also has been claimed to have very large non-linearities.…”

Section: Iintroductionmentioning

confidence: 99%

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

Huong

Birman

2003

Phys. Rev. B

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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.

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

Cited by 20 publications

References 17 publications

Engineered nanostructures exhibiting enhanced optical nonlinearity

Engineered nanostructures exhibiting enhanced optical nonlinearity

Hybridized quadrupole-dipole exciton effects in aCu2O-organic heterostructure

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

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