Hybridized quadrupole-dipole exciton effects in aCu2O-organic heterostructure

Abstract

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.

Influence of the image charge effect on excitonic energy structure in organic-inorganic multiple quantum well crystals

“…For example, the resonant coupling of excitons between organic molecules and inorganic semiconductor quantum wells (QWs) can lead to simultaneous high oscillator strength and strong optical nonlinearity. 2,3 For such applications [4][5][6] we need to clarify the fundamental properties of the excitons in QWs, focusing on the characteristic property of the hybrid materials.…”

Nearly Perfect Triplet-Triplet Energy Transfer from Wannier Excitons to Naphthalene in Organic-Inorganic Hybrid Quantum-Well Materials

“…The most interesting property of such systems is their ability to couple these two different types of excitons. It has been shown theoretically that such coupled excitons (the so-called ''hybrid excitons'') have unique optical features derived from both the large oscillator strength of the Frenkel excitons and the large nonlinearity of the Wannier excitons [1][2][3][4]. However, clear experimental observation of these unique features has not been reported yet.…”

“…Time-resolved photoluminescence measurements confirm that the transfer is triplet-triplet Dexter-type energy transfer from Wannier excitons in the inorganic well to the triplet state of naphthalene molecules in the organic barrier. Using measurements in the 10 -300 K temperature range, we also investigated the temperature dependence of the energy transfer.Organic-inorganic hybrid materials have attracted great interest because of their potential application to new types of optoelectronic devices [1][2][3][4][5][6][7][8][9]. In a typical hybrid material, low-dimensional Wannier excitons are formed in the inorganic part, and molecular excitations or Frenkel excitons are formed in the organic part.…”

“…Organic-inorganic hybrid materials have attracted great interest because of their potential application to new types of optoelectronic devices [1][2][3][4][5][6][7][8][9]. In a typical hybrid material, low-dimensional Wannier excitons are formed in the inorganic part, and molecular excitations or Frenkel excitons are formed in the organic part.…”

Evanescent quadrupole polariton

“…Although quadrupole excitons in cuprous oxide crystals are good candidates for BEC due to their narrow line-width and long life-time there are some factors impeding BEC [1,2]. One of these factors is that due to small but non negligible coupling to the photon bath, one must consider BEC of the corresponding mixed lightmatter states called polaritons [3].…”