Resonance-Induced Dynamic Triplet Exciton Population for Photoactivated Organic Ultralong Room Temperature Phosphorescence

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(29), P. 20449 - 20457

Published: July 11, 2024

Dynamically populating triplet excitons under external stimuli is desired to develop smart optoelectronic materials, but it remains a formidable challenge. Herein, we report resonance-induced excited state regulation strategy dynamically modulate the exciton population by introducing self-adaptive N-C═O structure phosphors. The developed phosphors activated high-power ultraviolet irradiation exhibited enhanced photoactivated organic ultralong room temperature phosphorescence (PA-OURTP) with lifetimes of up ∼500 ms. PA-OURTP was ascribed resonance variation-induced intersystem crossing generate excess excitons. excellent performance and deactivation time ambient conditions materials could function as reusable recorded medium for time-sensitive information encryption through optical printing. This study provides an effective approach regulating offers valuable guidance high-performance security printing applications.

Language: Английский

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Pyrene‐Alkyne‐Based Conjugated Porous Polymers with Skeleton Distortion‐Mediated •O2‐ and 1O2 Generation for High‐Selectivity Organic Photosynthesis

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: unknown

Published: May 31, 2024

Abstract Reactive oxygen species (ROS) play a crucial role in determining photocatalytic reaction pathways, intermediate species, and product selectivity. However, research on ROS regulation polymer photocatalysts is still its early stages. Herein, we successfully achieved series of modulations to the skeleton Pyrene‐alkyne‐based (Tetraethynylpyrene (TEPY)) conjugated porous polymers (CPPs) by altering linkers (1,4‐dibromobenzene (BE), 4,4′‐dibromobiphenyl (IP), 3,3′‐dibromobiphenyl (BP)). Experiments combined with theoretical calculations indicate that BE‐TEPY exhibits planar structure minimal exciton binding energy, which favors dissociation followed charge transfer adsorbed O 2 produce ⋅O − . Thus shows optimal activity for phenylboronic acid oxidation [3+2] cycloaddition. Conversely, BP‐TEPY significantly distorted. Its conjugation decreases, intersystem crossing (ISC) efficiency increases, makes it more prone resonance energy generate 1 Therefore, displays best [4+2] cycloaddition thioanisole oxidation. Both above reactant conversion selectivity exceed 99 %. This work systematically reveals intrinsic structure–activity relationship among CPPs, excitonic behavior, selective generation ROS, providing new insights rational design highly efficient CPPs photocatalysts.

Language: Английский

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Controlling Interchromophore Coupling in Diamantane-Linked Pentacene Dimers To Create a “Binary” Pair

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(15), P. 10875 - 10888

Published: April 5, 2024

Two isomeric pentacene dimers, each linked by a diamantane spacer, have been synthesized. These dimers are designed to provide experimental evidence support quantum mechanical calculations, which predict the substitution pattern on carbon-rich diethynyldiamantane spacer be decisive in controlling interpentacene coupling. Intramolecular singlet fission (i-SF) serves as probe for existence and strength of electronic coupling between two pentacenes, with transient absorption spectroscopy method choice characterize i-SF. 4,9-Substitution provides dimer (4,9-dimer) chromophores completely decoupled that, following photoexcitation, deactivates ground state analogous monomeric chromophore. Conversely, 1,6-substitution (1,6-dimer) that exhibits sufficiently strong drive i-SF, resulting correlated triplet M(T1T1) yields close unity free (T1 + T1) ca. 50%. Thus, effectively switches "on" or "off" chromophores, based pattern. The binary control contrasts other known molecular spacers only modulate pentacenes.

Language: Английский

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Pyrene‐Alkyne‐Based Conjugated Porous Polymers with Skeleton Distortion‐Mediated •O2‐ and 1O2 Generation for High‐Selectivity Organic Photosynthesis

Angewandte Chemie, Journal Year: 2024, Volume and Issue: unknown

Published: May 31, 2024

Abstract Reactive oxygen species (ROS) play a crucial role in determining photocatalytic reaction pathways, intermediate species, and product selectivity. However, research on ROS regulation polymer photocatalysts is still its early stages. Herein, we successfully achieved series of modulations to the skeleton Pyrene‐alkyne‐based (Tetraethynylpyrene (TEPY)) conjugated porous polymers (CPPs) by altering linkers (1,4‐dibromobenzene (BE), 4,4′‐dibromobiphenyl (IP), 3,3′‐dibromobiphenyl (BP)). Experiments combined with theoretical calculations indicate that BE‐TEPY exhibits planar structure minimal exciton binding energy, which favors dissociation followed charge transfer adsorbed O 2 produce ⋅O − . Thus shows optimal activity for phenylboronic acid oxidation [3+2] cycloaddition. Conversely, BP‐TEPY significantly distorted. Its conjugation decreases, intersystem crossing (ISC) efficiency increases, makes it more prone resonance energy generate 1 Therefore, displays best [4+2] cycloaddition thioanisole oxidation. Both above reactant conversion selectivity exceed 99 %. This work systematically reveals intrinsic structure–activity relationship among CPPs, excitonic behavior, selective generation ROS, providing new insights rational design highly efficient CPPs photocatalysts.

Language: Английский

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Heterogeneous singlet fission in a covalently linked pentacene dimer

Cell Reports Physical Science, Journal Year: 2024, Volume and Issue: 5(7), P. 102045 - 102045

Published: June 13, 2024

Molecular dimers are generally regarded as essential tools for probing structure-property relationships in condensed-phase systems, revealing complexities where structural tuning is challenging. Traditionally treated "static," with properties defined by their optimized geometry, we argue that "dynamic," exhibiting considerable conformational heterogeneity over time, which significantly influences interchromophore coupling strengths. Illustrating this, explore the singlet fission dynamics of a pentacene dimer linked phenyl-diketopyrrolopyrrole and acetylene bridges. The unrestricted rotations yield myriad rotational conformers, each altering processes, evident through excitation-energy-dependent transient absorption electron paramagnetic resonance spectroscopy. This necessitates considering not only broad distribution rate constants but also multidimensional potential-energy surfaces multiple sub-ensembles, leading to "heterogeneous fission." Consequently, these findings challenge prevailing static approach molecular photophysics, suggesting individual steps excited-state relaxation pathways cannot be delineated unique yields.

Language: Английский

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Macrocyclic Parallel Dimer Showing Quantum Coherence of Quintet Multiexcitons at Room Temperature

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(37), P. 25527 - 25535

Published: Sept. 9, 2024

Singlet fission (SF) is a promising approach in quantum information science because it can generate spin-entangled quintet triplet pairs by photoexcitation independent of temperature. However, still challenging to rationally achieve coherence at room temperature, which requires precise control the orientation and dynamics pairs. Here we show that multiexcitons be achieved temperature arranging two pentacene chromophores parallel close proximity within macrocycle. By making dynamic covalent Schiff-base bonds between aldehyde-modified derivatives, macrocyclic dimer-1 (

Language: Английский

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Synthesis, Photophysical, and Optical Limiting Properties of Twistacene-Functionalized Arenes

The Journal of Physical Chemistry B, Journal Year: 2024, Volume and Issue: 128(22), P. 5481 - 5488

Published: May 25, 2024

To realize the relationship of structure and property, four novel twistacene-functionalized arenes, namely, 1,4-bis(2,7-di-

Language: Английский

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Theoretical Investigation of Singlet Fission Processes in Organic Photovoltaics

Wiley Interdisciplinary Reviews Computational Molecular Science, Journal Year: 2025, Volume and Issue: 15(1)

Published: Jan. 1, 2025

ABSTRACT Singlet fission (SF) is a down‐conversion photophysical process involving transforming high‐energy singlet state into two lower‐energy triplet excitons. It has attracted extensive attention over the past decades because of its potential to break power conversion limit in photovoltaic devices. However, this material's complex, strongly correlated electronic properties and various packing structures pose challenges understanding intrinsic mechanisms limiting theory‐guided molecular design. In review, we summarize our theoretical work by studying structure, exciton‐phonon structure low‐excited dynamics several typical materials, clearly elucidating microscopic mechanism SF process. Subsequently, based on an in‐depth mechanism, use novel macrocyclic framework design intramolecular candidates hope improve energy efficiency SF‐based

Language: Английский

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Dual Charge‐Transfer Emission in Chalcone‐based Donor‐π‐Acceptor System and The Modulation of Down‐Conversion of Triplet Exciton with the Polarity of the Medium

Chemistry - A European Journal, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 31, 2025

Abstract Thermally activated delayed fluorescence (TADF) has recently emerged as a promising process with significant potential to advance organic light‐emitting diodes (OLEDs) for display applications. The donor‐acceptor system is well‐known molecular arrangement exhibiting TADF properties. However, our investigation into the chalcone‐based donor‐π‐acceptor (D‐π‐A) (SKG1) reveals that en‐one bridging unit in chalcone plays crucial role reverse intersystem crossing (rISC) and may be responsible existence of two conformational isomers. In stark contrast conventional endothermic process, designed molecule follows down‐converted cold rISC pathway also from higher‐lying triplet (T n ) state lowest singlet (S 1 (in toluene) remarkably short lifetime 350 ns. Additionally, this found sensitive polarity medium. UV‐vis‐NIR transient absorption spectroscopy an ultrafast (ISC) within <100 ps involvement higher lying process. This comprehensive research deepens understanding mechanism paves way developing next‐generation OLED materials using D‐π‐A‐based emitters.

Language: Английский

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Intramolecular Singlet Fission in Individual Graphene Nanoribbons─Competition with a Charge Transfer

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: March 19, 2025

Graphene nanoribbons (NRs) constitute a versatile platform for developing novel materials, where their structure governs optical, electronic, and magnetic properties while also shaping excited-state dynamics. Here, we investigate set of three twisted N-doped molecular NRs increasing length, obtained by linearly fusing perylene diimide to pyrene pyrazino- or thiadiazolo-quinoxaline residues. By employing various temperature-dependent time-resolved spectroscopy techniques, reveal how the flexible NR geometry promotes formation mixed electronic state with varying contributions from locally excited charge-transfer (CT) states. The fate this is highly sensitive geometry, solvent polarity. For shortest NR, intersystem crossing dominates deactivation pathway, efficiently generating triplets in low-polarity solvents. In contrast, extended NRs, intramolecular singlet fission (SF) takes place within single nanoribbon. This enabled enhanced superexchange coupling due pronounced push-pull nature existence multiple localized π-electron states caused heteroatom doping, thereby circumventing need dimeric interactions typically associated conventional SF systems. higher-polarity environments, evidence (diabatic) CT emerges. These findings underscore intricate relationship between energy levels, dynamics NRs.

Language: Английский

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