Superexchange mediated energy transfer in zinc(ii) porphyrin–free base porphyrin dimers: comparison of m- and p-bis(phenylethynyl) phenylene linked dimers

Asano, Motoko S.; Yamashita, Ken‐ichi; Kitabayashi, Masato; Kusama, Kazuki; Kagota, Daichi; Sugiura, Ken‐ichi

doi:10.1039/c1cp20539k

Cited by 14 publications

(10 citation statements)

References 22 publications

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“…As described, excitation spectra could not detect any trance of intramolecular energy transfer, which can be usually confirmed by the fluorescence excitation spectra. 28 One of the possibilities is energy transfer between two PFV units which have different repeat numbers and that are connected via a 3PV unit in a polymer chain. Although polymers studied in this work have rather narrow distribution of molecular sizes, there should be some species, which consist of two different PFV units in their repeat numbers (for example, C 6 F 5 -(PFV) 8 -3PV-(PFV) 12 -C 6 F 5 ).…”

Section: Macromoleculesmentioning

confidence: 99%

Time-Resolved Fluorescence Spectra in the End-Functionalized Conjugated Triblock Copolymers Consisting of Poly(fluorene vinylene) and Oligo(phenylene vinylene): Proposal of Dynamical Distortion in the Excited State

et al. 2015

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Time-resolved fluorescence study has been explored for end-functionalized conjugated triblock copolymers consisting of poly(9,9-di-n-octylfluorene-2,7-vinylene)s (PFVs, FV repeat units ca. 10 or 20) and oligo(2,5-dialkoxy-1,4-phenylenevinylene)s [OPV, alkoxy = O(CH 2 ) 2 OSi i Pr 3 , 3 or 7 PV repeat unit] as the middle segment. Unit (FV and PV) length dependence of each block on fluorescence was examined. The polymer sample having three PV repeat units as the middle segment with C 6 F 5 end-groups, [10PFV-3PV]F 2 , showed time-dependent fluorescence spectra, in which relative intensities of the vibronic bands increase in later delay time, whereas similar observations were not seen in the other polymer samples containing 7PV as the middle segment even by varying the PFV chain lengths (ca. 20) or the end-group (C 6 F 5 vs C 6 H 5 ). Timeresolved of fluorescence signals for [10PFV-3PV]F 2 can be analyzed by assuming two components: one is a faster decay component and the other is a slower red component, which rises with the time constant of the former one. On the other hand, the other three polymer samples showed single-exponential decays without significant wavelength dependence. Dynamical structural relaxation in the excited state is proposed as the origin of time dependence of the fluorescence spectra in the polymer having 3PV repeat unit on the basis of analysis of time-resolved fluorescence signals as well as viscosity dependence. ■ INTRODUCTIONConjugated polymers are of continuing interest as organic electronics due to their promising applications in optoelectronic and electrochemical devices, 1−5 such as photovoltaic cells, 3b light-emitting diodes, 5c,6 sensors, 5d,7 electrochromics, 8 and field-effect transistors. 5a,b,9 The synthesis of structurally regular, chemically pure polymers by development of new synthetic methods attracts notable attention 1 because their device performances are governed by the structural regularity, chemical purity, and supramolecular order. 2,3 Emerging applications of conjugated polymers require the patterning of materials on the nanometers length scale, and block copolymers made of covalently linked polymers represent an ideal route to control the self-assembly of the nanosized morphologies. Formation of regular one-dimensional conjugated structures on the nanoscale should be thus expected by exploiting the specific assembling properties of rod−coil block copolymers. 10−13 End-group modification of conjugated polymers has also been considered as an attractive topic of investigation because the important properties that have been demonstrated for end-functional conjugated polymers and the significant effect end-groups can have on electronic properties. For example, simple end-capping of conjugated polymers via postpolymerization reactions showed improvement in the performance of bulk heterojunction photovoltaic devices by eliminating traps for charge carriers. 14 Many reports concerning poly(fluorene)s (PFs) containing discrete end-groups (such as triarylamines, perylene mon...

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Section: Macromoleculesmentioning

confidence: 99%

Time-Resolved Fluorescence Spectra in the End-Functionalized Conjugated Triblock Copolymers Consisting of Poly(fluorene vinylene) and Oligo(phenylene vinylene): Proposal of Dynamical Distortion in the Excited State

et al. 2015

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“…The short lifetime component can be associated to the characteristic time constant of the energy transfer, and the long lifetime component may be the decay of the excited free Ru. This suggests that the energy transfer rate from the excited Ru to TAPP is ∼1.8 × 10 9 s −1 , which is similar to through-space singlet energy transfer for donor-acceptor distances approaching 3.5-3.6Å [53,54]. In addition, the fs fluorescence up-conversion data (see Figure 6B) show a very fast decay of the Ru excited state with a characteristic time constant of 160 fs, providing a clear indication for static quenching.…”

Section: Ru-tapp Associationmentioning

confidence: 71%

Photoinduced energy and electron transfer in rubrene–benzoquinone and rubrene–porphyrin systems

Khan¹,

Abbas²,

Aly³

et al. 2014

Chemical Physics Letters

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“…One distinct character for TADPP2‐TT and TADPP3 is that their HOMOs and LUMOs show similar distributions not only on the DPP units, but also extending to the acetylene and part of the benzene core. Conjugation is then broken in the meta ‐substituted benzene core in which two atoms in the benzene core have no electron population in the calculated HOMOs and LUMOs . Furthermore, the frontier orbitals of TADPP2‐TT show that the 2,2′:5′2′′‐terthiophene moiety does not contribute to the first excited state, which suggests that TADPP2‐TT can be treated as a simple DPP dimer.…”

Section: Resultsmentioning

confidence: 99%

“…Conjugation is then broken in the meta-substituted benzene core in which two atoms in the benzene core have no electron population in the calculated HOMOsa nd LUMOs. [18] Furthermore, the frontier orbitals of TADPP2-TT show that the 2,2':5'2''-ter- In addition, the geometries of the excited states of TADPP2-TT and TADPP3 were optimized to determine the electronic coupling between branches. The corresponding bond lengths of the ground and excited states are showni nS ection S3 in the Supporting Information.…”

Section: Quantum Chemical Calculationsmentioning

confidence: 99%

Excitation Energy Transfer in meta‐Substituted Phenylacetylene Multibranched Chromophores

et al. 2016

Chemistry An Asian Journal

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A comprehensive investigation into the spectral properties and excitation energy transfer in di- or tribranched dithienyldiketopyrrolopyrrole (DPP) molecules with meta-substituted benzene as a central core (TADPP2-TT and TADPP3), by means of steady-state and transient measurements and quantum chemical calculations, is reported. Excitation in the meta-substituted chromophores is localized on one of the DPP units in the branching molecules owing to the disruption of conjugation by meta substitution for both TADPP2-TT and TADPP3. Weak electronic couplings result from the long distance between the DPP chromophores and the steric effects from the attached side chains on DPP. The attachment of the acetylene linker in each branch, which has a very low twisting barrier, could also play an important role in reducing the interaction between DPP chromophores. The dynamics of the excited states show that excitation energy transfer occurs on the picosecond scale, which is attributed to the incoherent hopping mechanism.

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Superexchange mediated energy transfer in zinc(ii) porphyrin–free base porphyrin dimers: comparison of m- and p-bis(phenylethynyl) phenylene linked dimers

Cited by 14 publications

References 22 publications

Time-Resolved Fluorescence Spectra in the End-Functionalized Conjugated Triblock Copolymers Consisting of Poly(fluorene vinylene) and Oligo(phenylene vinylene): Proposal of Dynamical Distortion in the Excited State

Time-Resolved Fluorescence Spectra in the End-Functionalized Conjugated Triblock Copolymers Consisting of Poly(fluorene vinylene) and Oligo(phenylene vinylene): Proposal of Dynamical Distortion in the Excited State

Photoinduced energy and electron transfer in rubrene–benzoquinone and rubrene–porphyrin systems

Excitation Energy Transfer in meta‐Substituted Phenylacetylene Multibranched Chromophores

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