One-, two- and three-photon spectroscopy of π-conjugated dendrimers: cooperative enhancement and coherent domains

Drobizhev, Mikhail; Rebane, Aleksander; Suo, Zhiyong; Spangler, Charles W.

doi:10.1016/j.jlumin.2004.10.009

Cited by 101 publications

(73 citation statements)

References 56 publications

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“…28) [144,145]. The TPA efficiency varies in the ratio 1.0; 4.1; 8.4; 14.1 from the parent Re1 to the second generation dendrimer Re4, as reported in Table 4 4 .…”

Section: Organic Systemsmentioning

confidence: 99%

Excitonically Coupled Oligomers and Dendrimers for Two-Photon Absorption

Andraud¹,

Fortrie²,

Barsu³

et al. 2008

Advances in Polymer Science

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International audienceThe first part of this review presents the state of the art on two-photon absorbing molecules. Earlyworks concerned the optimization of dipolar push–pull molecules. Recently, the synthesis of linearand branched centrosymmetrical quadrupolar molecules led to higher nonlinearities, but still far from reachingthe fundamental limits of molecular two-photon cross-sections.The second part of this review summarizes our theoretical and experimental results on fluorene-basedoligomers, and branched oligomers (V-shape molecules and dendrimers). They are model molecules to investigatean alternative approach based on spatial assemblies of nonsubstituted π-electronsystems that are coupled by dipole–dipole interactions. In all geometries, two-photon absorptioncross-sections have superlinear dependencies that depend on coupling energies and oligomer sizes. Theseresults are well rationalized by an excitonic model based on N interactingthree-level systems. Analytical expressions for one-photon and two-photon energies and absorption strengthsare derived for linear oligomers. An accurate calculation of large exitonic systems is obtained by diagonalizingthe Hamiltonian operator on a reduced basis set

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“…28) [144,145]. The TPA efficiency varies in the ratio 1.0; 4.1; 8.4; 14.1 from the parent Re1 to the second generation dendrimer Re4, as reported in Table 4 4 .…”

Section: Organic Systemsmentioning

confidence: 99%

Excitonically Coupled Oligomers and Dendrimers for Two-Photon Absorption

Andraud¹,

Fortrie²,

Barsu³

et al. 2008

Advances in Polymer Science

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“…[1][2][3][4][5][6] In recent years, after investigation of "simple" chromophores, [7][8][9][10][11][12][13][14] attention has progressively moved toward more complex structures, with the aim of optimising the relevant TPA cross section s 2 . In particular, the multipolar and/or branched compounds such as dendrimers that are currently being investigated result in exaltation [18,20,30,31,33,36] or reduction [19] of the desired response or even simple additive effects [15,19] with respect to their monomeric "bricks". Theoretical modelling of such structures is not easy, and even more subtlety is needed to recognise which parameters are accountable for the response of the system.…”

Section: Introductionmentioning

confidence: 99%

Linear and Two‐Photon Absorption Properties of Interacting Polar Chromophores: Standard and Unconventional Effects

et al. 2006

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Investigations into the effects of electrostatic interactions on linear and two-photon absorption (TPA) properties are probed using a reference polar chromophore and different related compounds. Compounds in which a passive charge is present near the active chromophore, as well as dimers of the reference molecule, were studied. The combined experimental and theoretical investigation demonstrates that strong modulation of the properties can be attained. In particular, the TPA response of dimers is heavily affected by unconventional excitonic effects, that is, beyond the standard Heitler-London approximation. These effects, which stem from purely electrostatic interactions, lower the nonlinear optical response in the investigated case by an additional amount (up to 20%), and are expected to enhance the TPA cross section in other supramolecular alignments. Electrostatic interactions cannot be overlooked when modelling or investigating highly concentrated and/or confined samples, as are usually needed in many applications. The correct knowledge of their effects can be exploited to guide engineering at the molecular and supramolecular level.

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“…It is reasonable to limit a sum-over-states expansion to three closest energy levels (three level model), namely, the ground state (index 0), two-photon excited state (f), and a main intermediate electronic state (i), then the peak crosssection can be expressed as [25] …”

Section: Two-photon Absorption Cross-sectionsmentioning

confidence: 99%