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Kippelen, Bernard; Blanche, P.-A.; Schülzgen, Axel; Fuentes-Hernández, Canek; Ramos‐Ortíz, Gabriel; Wang, J.‐F.; Peyghambarian, N.; Marder, Seth R.; Leclercq, A.; Beljonne, David; Brédas, Jean Luc

doi:10.1002/1616-3028(20020916)12:9<615::aid-adfm615>3.0.co;2-o

Cited by 16 publications

(10 citation statements)

References 23 publications

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“…Experimental details, calculation of radiative decay times, complete ref b. This material is available free of charge via the Internet at .…”

Section: Supporting Information Availablementioning

confidence: 99%

“…Organic materials with strong two-photon absorption (TPA) properties have motivated the creation of new photonic devices , The enhanced TPA properties have been theoretically investigated, and the importance of charge-transfer character and excitation delocalization has been shown. − Previously, time-resolved spectroscopic studies have been used to probe the mechanism of the enhancement. , However, the basic structure−function relationships regarding excited-state dynamics (transition moments, electronic coupling between levels, interaction with solvent) and enhanced TPA properties remain unclear.…”

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confidence: 99%

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Ultrafast Dynamics in Multibranched Structures with Enhanced Two-Photon Absorption

2005

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The understanding of the mechanism of the enhanced two-photon absorption (TPA) in multibranched chromophore systems is of importance to the design of materials with the large TPA cross-sections and for future applications. In this communication, the mechanism of enhanced TPA properties is investigated. For a dendritic model system, the excited-state dynamics for both population (T1-process) and phase relaxation (T2-process) processes involved are investigated by a combination of time-resolved spectroscopic techniques. The results of time-resolved fluorescence anisotropy are compared with previous results obtained from other branched chromophore systems. It is found that the PRL-701 trimer system, which possesses the large enhancement of two-photon absorption cross-section, gives a faster anisotropy decay (fluorescence upconversion and transient absorption), a longer population relaxation time (fluorescence lifetime), and a weaker coupling to the solvent (a larger photon echo peak shift initial value). New strategies for rational design of large TPA materials can be achieved based on a better understanding of the mechanism of the enhancement.

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“…Experimental details, calculation of radiative decay times, complete ref b. This material is available free of charge via the Internet at .…”

Section: Supporting Information Availablementioning

confidence: 99%

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confidence: 99%

Ultrafast Dynamics in Multibranched Structures with Enhanced Two-Photon Absorption

2005

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“…Currently, there are intense research efforts focused on organic materials with large nonlinear optical (NLO) properties. − Developments in synthesis and molecular engineering of organic chromophores and macromolecules have resulted in new materials with high NLO and two-photon absorption (TPA) properties. − Some of these materials have progressed to the level of real applications as well. − Among several geometries investigated for better NLO and TPA properties, branched organic chromophores with donor-π-acceptor configuration − have gained a great deal of recent interest, which is largely due to their enhanced TPA and NLO properties with respect to their monomer counterparts. Several experimental and theoretical investigations have been carried out to have a mechanistic understanding of structure−property relationships of TPA cross-sections. − It has been shown from the measurements that donor−acceptor strength, conjugation length, geometry, and nature of ground and excited states have significant influence on TPA cross-sections .…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3] Developments in synthesis and molecular engineering of organic chromophores and macromolecules have resulted in new materials with high NLO and two-photon absorption (TPA) properties. [4][5][6][7] Some of these materials have progressed to the level of real applications as well. [8][9][10][11][12][13][14] Among several geometries investigated for better NLO and TPA properties, branched organic chromophores with donor-π-acceptor configuration [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] have gained a great deal of recent interest, which is largely due to their enhanced TPA and NLO properties with respect to their monomer counterparts.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast Excited State Relaxation Dynamics of Branched Donor-π-Acceptor Chromophore: Evidence of a Charge-Delocalized State

2006

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Excited-state dynamics and complete transient absorption features of the trimer tris-4,4',4' '-(4-nitrophenyleethynyl)triphenylamine and the monomer 4-N,N-(dimethylamino)-4'-nitrotolane have been obtained from femtosecond pump-probe spectroscopy. The measurements are carried out to understand the mechanism behind enhanced two-photon absorption cross-sections of branched systems over their linear counterparts. Absorption and emission transition dipole moments of monomer and trimer in toluene have suggested that the emitting state of trimer is different from the monomer and probably is arising from the charge-delocalized C(3) symmetry state. Ultrafast transient absorption measurements on these molecules have spectroscopically validated the presence of an initial electron delocalized state with the C(3) symmetry state in the trimer molecule. The results have shown that there is a slower rate of internal conversion from the C(3) symmetry state to intramolecular charge transfer of trimer suggesting a barrier between them. Also, presence of a charge-stabilized state and involvement of a nonemissive state in the excited-state deactivation has been observed for both monomer and trimer.

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“…The HOMO levels of PVCz (and CzEPA), 7-DCST, and TNF are −5.9 [20], −5.9 [12], and −7.9 eV [21], respectively. These HOMO levels mean that 7-DCST and TNF does not work as a deep trap for hole transport hopping through PVCz and CzEPA.…”

Section: Resultsmentioning

confidence: 99%

Quickly Updatable Hologram Images Using Poly(N-vinyl Carbazole) (PVCz) Photorefractive Polymer Composite

et al. 2012

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Quickly updatable hologram images using photorefractive (PR) polymer composite based on poly(N-vinyl carbazole) (PVCz) is presented. PVCz is one of the pioneer materials of photoconductive polymers. PR polymer composite consists of 44 wt % of PVCz, 35 wt % of 4-azacycloheptylbenzylidene-malonitrile (7-DCST) as a nonlinear optical dye, 20 wt % of carbazolylethylpropionate (CzEPA) as a photoconductive plasticizer and 1 wt % of 2,4,7-trinitro-9-fluorenone (TNF) as a sensitizer. PR composite gives high diffraction efficiency of 68% at E = 45 V μm−1. Response speed of optical diffraction is the key parameter for real-time 3D holographic display. The key parameter for obtaining quickly updatable holographic images is to control the glass transition temperature lower enough to enhance chromophore orientation. Object image of the reflected coin surface recorded with reference beam at 532 nm (green beam) in the PR polymer composite is simultaneously reconstructed using a red probe beam at 642 nm. Instead of using a coin object, an object image produced by a computer was displayed on a spatial light modulator (SLM) and used for the hologram. The reflected object beam from an SLM was interfered with a reference beam on PR polymer composite to record a hologram and simultaneously reconstructed by a red probe beam.

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Cited by 16 publications

References 23 publications

Ultrafast Dynamics in Multibranched Structures with Enhanced Two-Photon Absorption

Ultrafast Dynamics in Multibranched Structures with Enhanced Two-Photon Absorption

Ultrafast Excited State Relaxation Dynamics of Branched Donor-π-Acceptor Chromophore: Evidence of a Charge-Delocalized State

Quickly Updatable Hologram Images Using Poly(N-vinyl Carbazole) (PVCz) Photorefractive Polymer Composite

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