Oligothiophene as photonic/electronic property modulator

Kim, O.-K; Lee, K.-S; Huang, Zhiyuan; Heuer, William B.; Paik-Sung, C.S

doi:10.1016/s0925-3467(02)00200-8

Cited by 31 publications

(21 citation statements)

References 24 publications

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“…In the quest of improving NLO properties, attention has been essentially focused on dipolar molecules for several decades. [1][2][3] More recently, quadrupolar systems have been designed and investigated [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and have shown improved properties, in particular with respect to the trade-off between optical transparency and NLO performance. Lately, attention has turned toward multipolar [22][23][24][25][26][27][28][29][30][31][32][33] and branched structures including dendrimers.…”

Section: Introductionmentioning

confidence: 99%

Effects of (Multi)branching of Dipolar Chromophores on Photophysical Properties and Two-Photon Absorption

et al. 2005

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To investigate the effect of branching on linear and nonlinear optical properties, a specific series of chromophores, epitome of (multi)branched dipoles, has been thoroughly explored by a combined theoretical and experimental approach. Excited-state structure calculations based on quantum-chemical techniques (timedependent density functional theory) as well as a Frenkel exciton model nicely complement experimental photoluminescence and one-and two-photon absorption findings and contribute to their interpretation. This allowed us to get a deep insight into the nature of fundamental excited-state dynamics and the nonlinear optical (NLO) response involved. Both experiment and theory reveal that a multidimensional intramolecular charge transfer takes place from the donating moiety to the periphery of the branched molecules upon excitation, while fluorescence stems from an excited state localized on one of the dipolar branches. Branching is also observed to lead to cooperative enhancement of two-photon absorption (TPA) while maintaining high fluorescence quantum yield, thanks to localization of the emitting state. The comparison between results obtained in the Frenkel exciton scheme and ab initio results suggests the coherent coupling between branches as one of the possible mechanisms for the observed enhancement. New strategies for the rational design of NLO molecular assemblies are thus inferred on the basis of the acquired insights.

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Section: Introductionmentioning

confidence: 99%

Effects of (Multi)branching of Dipolar Chromophores on Photophysical Properties and Two-Photon Absorption

et al. 2005

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“…We selected biphenyl (BP) or fluorene (Fl) central units, which allow the tuning of the electronic delocalization along the conjugated backbone in the ground state by modulation of the twist angle between the two halves of the molecules 40. It should be noted that the fluorene building block was successfully used in the design of both dipolar46, 83 and quadrupolar systems with large multiphoton absorption,40, 59, 69 owing to the planarity it provides. Conjugated rods built from arylene–ethynylene and/or arylene–vinylene oligomers were investigated to maintain fluorescence and to modulate the electronic communication between the end‐groups and the core of the molecules.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Fluorescence, and Two‐Photon Absorption of a Series of Elongated Rodlike and Banana‐Shaped Quadrupolar Fluorophores: A Comprehensive Study of Structure–Property Relationships

Mongin

Porrès

Charlot

et al. 2007

Chemistry A European J

238

204

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An extensive series of push-push and pull-pull derivatives was prepared from the symmetrical functionalization of an ambivalent core with conjugated rods made from arylenevinylene or arylene-ethynylene building blocks, bearing different acceptor or donor endgroups. Their absorption and photoluminescence as well as their two-photon absorption (TPA) properties in the near infrared (NIR) region have been systematically investigated in order to derive structure-property relationships and lay the guidelines for both spectral tuning and amplification of molecular TPA in the target region. Whatever the nature of the core or of the connectors, push-push systems were found to be more efficient than pull-pull systems and planarization of the core (fluorene vs biphenyl) always leads to an increase of the TPA crosssections. At contrary, increasing the conjugation length as well as replacement of a phenylene moiety by a thienylene moiety in the conjugated rods did not necessarily lead to increased TPA responses. The present study also demonstrated that the topology of the conjugated rods can dramatically influence the TPA properties. This is of particular interest in terms of molecular engineering for specific applications since both TPA properties and photoluminescence characteristics can be considerably affected. It thus becomes possible to optimize the transparency/TPA and fluorescence/TPA efficiency trade-offs, for optical limiting in the red-NIR region (700-900 nm) and TPEF microscopy applications, respectively.

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“…A number of factors influence the TPA magnitude, among which electronic delocalization and intramolecular charge transfer phenomena. In recent years, considerable effort has been devoted to the design and investigation of chromophores with large TPA cross-section, exploring in particular dipolar 1-8 and quadrupolar, 2,4,6,[8][9][10][11][12][13][14][15][16][17][18][19][20][21] structures. Lately, attention has turned towards multipolar [22][23][24][25][26][27][28][29][30][31][32] and branched structures such as dendrimers.…”

Section: Introductionmentioning

confidence: 99%

Branching of dipolar chromophores: effects on linear and nonlinear optical properties

Katan¹,

Terenziani²,

Droumaguet³

et al. 2005

Linear and Nonlinear Optics of Organic Materials V

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C. Katan present address: CNRS UMR6082 FOTON, INSA de Rennes, 20 avenue des Buttes de Coësmes, CS 70839, 35708 RENNES cedex 7, FranceInternational audienceStructurally related chromophores of different symmetry (dipolar, V-shaped, octupolar) are investigated and compared for elucidation of the combined role of branching and charge symmetry on absorption, photoluminescence and two-photon absorption (TPA). Their design is based on the assembly of one, two or three -conjugated dipolar branches on a central core. Two series of branched structures obtained from a central triphenylamine core and dipolar branches having different charge-transfer characters are investigated: photophysical properties are studied and TPA spectra are determined through two-photon excited fluorescence experiments using fs pulses in the 700-1000 nm range. Calculations based on time-dependent quantum-chemical approaches, as well as the Frenkel exciton model, complement experimental findings. Experiments and theory reveal that a multidimensional intramolecular charge transfer takes place from the central electron-donating moiety to the periphery of the branched molecules upon excitation, whereas fluorescence stems from a dipolar branch. Symmetry and inter-branch electronic coupling are found to be responsible for amplification of the TPA response of branched compounds with respect to their monomeric analogues. In particular, an enhancement is observed in regions where the TPA bands overlap, and TPA activation is obtained in spectral regions where the dipolar analogue is almost two-photon transparent. Thus, appropriate tuning of the number of branches, of the coupling between them, and modulation of intramolecular charge transfer from core to periphery open the way for substantial improvement of TPA efficiency or TPA induction in desired spectral regions

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Oligothiophene as photonic/electronic property modulator

Cited by 31 publications

References 24 publications

Effects of (Multi)branching of Dipolar Chromophores on Photophysical Properties and Two-Photon Absorption

Effects of (Multi)branching of Dipolar Chromophores on Photophysical Properties and Two-Photon Absorption

Synthesis, Fluorescence, and Two‐Photon Absorption of a Series of Elongated Rodlike and Banana‐Shaped Quadrupolar Fluorophores: A Comprehensive Study of Structure–Property Relationships

Branching of dipolar chromophores: effects on linear and nonlinear optical properties

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