Organic Molecular Solids

Schwoerer, M.; Wolf, Hans Christoph

doi:10.1002/9783527618651

Cited by 165 publications

(254 citation statements)

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“…This agrees with our previous predictions using time-dependent density functional theory (TD-DFT) 47 and can be understood as arising from the coulomb interaction energy being larger than the resonance interaction energy. 63 This red-shift is typical of molecular dimers in the literature, independent of parent chromophore. 39,40,[42][43][44]64 The most striking feature in the BT1 dimer electronic absorption spectrum is the split band in the UV region with peaks at 309 and 275 nm (the smaller peak at 296 nm is assigned to a vibronic progression tied to the 309 nm absorption).…”

Section: Introductionmentioning

confidence: 83%

Solution-Phase Singlet Fission in a Structurally Well-Defined Norbornyl-Bridged Tetracene Dimer

2016

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The photophysics of a norbornyl-bridged covalent tetracene (Tc) dimer BT1 and a monomer analogue Tc-e were studied in room-temperature nonpolar solvents. Notably in BT1, a Davydov-split band is observed in UV absorption, heralding interchromophore electronic interactions. Emission spectra indicate an acene-like vibronic progression mirroring the lowest-energy visible absorption. For BT1, this argues against excited-state excimer formation. Evidence of intramolecular singlet fission (SF) comes from a comparison of time-resolved emission decay signals collected for BT1 versus Tc-e in toluene. In BT1, the multiexcitonic (1)TT state is produced in 70 ns in 6% yield. A ratio of fission versus fusion rate constants provides an experimental measure of the SF reaction free energy at 52 meV in good agreement with previous calculations. The low SF yield corroborates our expectations that orbital symmetry effects on diabatic coupling for SF are important for dimers that cannot rely on more favorable thermodynamics.

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Section: Introductionmentioning

confidence: 83%

Solution-Phase Singlet Fission in a Structurally Well-Defined Norbornyl-Bridged Tetracene Dimer

2016

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“…The effect of the external electric field is to modify the Coulomb potential profile destabilizing the excitonic levels. [33] In this situation the exciton can dissociate, provided that a density of states for charge transfer is available in the surrounding of the emitter molecule. This last condition is not satisfied for the type I alignment.…”

Section: Discussionmentioning

confidence: 99%

Effect of Electric Field on Coulomb‐Stabilized Excitons in Host/Guest Systems for Deep‐Blue Electrophosphorescence

Haneder

Como

Feldmann

et al. 2009

Adv Funct Materials

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Here, a study of the electric field induced quenching on the phosphorescence intensity of a deep‐blue triplet emitter dispersed in different host materials is presented. The hosts are characterized by a higher triplet excitonic level with respect to the emitter, ensuring efficient energy transfer and exciton confinement, whereas they differ in the highest occupied molecular orbital (HOMO) alignment, forming type I and type II host/guest heterostructures. While the type I structure shows negligible electric field induced quenching, a quenching up to 25% for the type II at a field of 2 MV/cm is reported. A similar quenching behaviour is also reported for thin films of the pure emitter, revealing an important luminescence loss mechanism for aggregated emitter molecules. These results are interpreted by considering Coulomb stabilized excitons in the type II heterostructure and in the pure emitter, that become very sensitive to dissociation upon application of the field. These results clarify the role of external electric field quenching on the phosphorescence of triplet emitters and provide useful insights for the design of deep‐blue electrophosphorescent devices with a reduced efficiency roll‐off.

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“…3 In organic semiconductors, weak van der Waals and hydrogen interactions govern the formation of crystal structures. In hybrid materials both scenarios are possible.…”

Section: ■ Introductionmentioning

confidence: 99%

Influence of π-Iodide Intermolecular Interactions on Electronic Properties of Tin(IV) Iodide Semiconducting Complexes

et al. 2016

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Coordination compounds with a tin center surrounded by both organic and inorganic ligands ([SnI4{(C6H5)3PO}2], [SnI4{(C6H5)2SO}2], and [SnI4(C5H5NO)2]) acting as molecular semiconductors are in the spotlight of this article. This is a new class of hybrid semiconducting materials where optoelectronic properties of inorganic core (SnI4) were tuned by organic ligands. The valence band is located at the inorganic portion of the molecule while the conduction band is made of carbon-based orbitals. This suggests the great importance of hydrogen bonds where iodine atoms play the role of an acceptor. Weak intermolecular interactions between iodine atoms and aromatic rings are essential in a band structure formation. These materials form orange-red crystals soluble in most of organic solvents. Their semiconducting properties are addressed experimentally via photovoltage measurements, as well as theoretically, using DFT and semiempirical approaches.

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Organic Molecular Solids

Cited by 165 publications

References 0 publications

Solution-Phase Singlet Fission in a Structurally Well-Defined Norbornyl-Bridged Tetracene Dimer

Solution-Phase Singlet Fission in a Structurally Well-Defined Norbornyl-Bridged Tetracene Dimer

Effect of Electric Field on Coulomb‐Stabilized Excitons in Host/Guest Systems for Deep‐Blue Electrophosphorescence

Influence of π-Iodide Intermolecular Interactions on Electronic Properties of Tin(IV) Iodide Semiconducting Complexes

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