Dynamics of vibrationally coupled intersystem crossing in state-of-the-art organic optoelectronic materials

Communications Chemistry, Journal Year: 2025, Volume and Issue: 8(1)

Published: March 18, 2025

This work investigates intersystem crossing (ISC) induced by spin-orbit coupling (SOC) in state-of-the-art non-fullerene acceptors (NFAs). A quantum chemistry study analyzed SOC 10 NFAs using the optimized geometry of ground state (OGGS), revealing importance excited-state character (local or charge transfer) determining SOC. However, ISC rates calculated with Marcus formalism were significantly lower than experimental values, showing that three-state model (S1, T1, and T2) is insufficient. simplified method to calculate coupled probabilities was proposed, leveraging a walk on one-dimensional graph. approach aligned data explained Y6's higher triplet efficiency compared ITIC-like NFAs. Further, dihedral angle (ϕ) IT-4Cl Y6 analyzed. unique potential energy curve (PEC) showed minimum at ϕ ≈ 90o. Using PECs, refined, via vibrations. Finally, Wentzel-Kramers-Brillouin (WKB) approximation photoluminescence low temperatures, highlighting non-adiabatic phenomena crucial for understanding photophysics organic semiconductors. Triplet states act as channels enhance recombination, reducing optoelectronic semiconductor devices. Therefore, controlling these can contribute improving solar cells (OSCs) light-emitting diodes (OLEDs). Controlling populations singlet donor-acceptor conjugated molecules prerequisite developing In this work, authors propose methodology determine probability rate crossover between systems acceptors, explaining their properties based walks.

Language: Английский

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Dynamic excitons in organic light-emitting systems

The Journal of Chemical Physics, Journal Year: 2025, Volume and Issue: 162(6)

Published: Feb. 10, 2025

Light-emitting molecules have been extensively studied due to their potential and wide variety of applications from optoelectronic devices biomedical applications. To fully understand rationalize the light-emitting process for innovation next-generation applications, it is vital reveal dynamic behavior excitons, where excited electronic states (locally excited, charge transfer, separated states), spin multiplicity, motion atomic nucleus are interacting each other. Here, we will show our recent progress on systems developed under “Dynamic Exciton” project in Japan.

Language: Английский

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Theoretical Study for Constructing Red Multiple-Resonance Thermally Activated Delayed Fluorescence Molecules with Narrowband Emission by Donor Engineering Strategy

Chinese Journal of Physics, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 1, 2025

Language: Английский

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The Role of Chalcogen Substitution and Helical Frameworks in Designing Efficient Chiral Multi‐Resonant TADF Emitters

Advanced Optical Materials, Journal Year: 2025, Volume and Issue: unknown

Published: March 7, 2025

Abstract Multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters that display efficient reverse intersystem crossing (RISC) rates and circularly polarized luminescence (CPL) are of great interest for next‐generation organic light‐emitting diode (OLED) applications, owing to their narrowband emission, high efficiency, remarkable color purity. Here, the photophysical chiroptical properties three series molecules derived from boron/nitrogen‐embedded MR cores by systematically introducing chalcogen atoms (O, S, Se) and/or incorporating ortho‐fused benzo or naphtho groups investigated. Highly correlated quantum‐chemical calculations reveal steric repulsions resulting positions induce molecular distortions twist backbone into helical structures, which enhances chiral properties; incorporation heavier chalcogens increases spin–orbit coupling (SOC), leading enhanced RISC rates. These findings demonstrate several considered exhibit radiative decay (≈10 8 s − ¹), substantial 4 –10 values dissymmetry factor g order 10 −3 , makes them potential candidates CPL applications. Overall, this study highlights complex interplay among substitution, structural modifications, electronic structure in governing MR‐TADF emitters, offers valuable insight rational design CPL‐enabled OLEDs.

Language: Английский

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The Role of Theoretical Calculations for INVEST Systems: Complementarity Between Theory and Experiments and Rationalization of the Results

Advanced Optical Materials, Journal Year: 2025, Volume and Issue: unknown

Published: March 5, 2025

Abstract Here, the key role played by theoretical calculations for molecules presenting an inverted singlet‐triplet excited state (e.g. S 1 and T ) energy difference, or Δ E ST < 0, whose interest has steadily raised in recent years fostered experimental advances showing negative values a collection of real‐world systems is reviewed. The evolution computational efforts from pioneering on reduced set prototypical covered, to high‐throughput virtual screenings thousands identify new molecular scaffolds tune properties other than excitation energies, describe necessary benchmarking methods done parallel along years. Overall, complementarity prompted discovery more displaying 0 values, basic design principles are rationalized thus reviewed here too, while allowing at same time find which offer reasonable trade‐off between accuracy cost.

Language: Английский

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Bayesian Molecular Optimization for Accelerating Reverse Intersystem Crossing

Chemical Science, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Spin conversion in molecular excited states is crucial for the development of next-generation optoelectronic devices.

Language: Английский

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Narrow‐Band Emission of Asymmetric 1,3‐Substituted Pyrene‐Based Deep‐Blue Emitters and Application in OLEDs

Advanced Optical Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 24, 2024

Abstract High‐efficiency organic blue light‐emitting materials with narrow‐band emission are fundamental components for constructing high color purity and resolution in high‐performance diode (OLED) devices. Herein, new pyrene‐based emitters ( 8 – 10) synthesized by asymmetrically introducing biphenyl triphenylamine units at the 1‐ 3‐positions of pyrene, respectively. Due to steric effect through‐space conjugation, synergistic effects both groups not only boost these 10 (CIE y < 0.11) aggregation‐induced (AIE) characteristics fluorescence quantum yield (>0.68), but also endow narrow full width half maxima (FWHM) (≤36 nm) crystallized state (FWHM ≤ 55 nm film state). The EL spectra nondoped OLEDs exhibit a maximum (λ max em ) range 448–453 0.12). compounds doped‐OLEDs show λ 443–445 CIE 0.08, FWHM 57–61 nm. compound ‐based doped OLED displays an impressive performance brightness 9756 cd m −2 external efficiency 2.58%.

Language: Английский

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Toward Efficient Modeling of Nonradiative Decay in Extended INVEST: Overcoming Computational Challenges in Quantum Dynamics Simulations

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(44), P. 11042 - 11050

Published: Oct. 29, 2024

In recent years, an increasing number of fully organic molecules capable thermally activated delayed fluorescence (TADF) have been reported, often with very small or even inverted singlet–triplet (INVEST) energy gaps. These typically exhibit complex photophysics due to the close levels multiple singlet and triplet states, which create various transition pathways toward emission. A predictive model for rates these transitions is thus essential assessing suitability new materials light-emitting devices. Quantum Dynamics (QD) calculations are ideal this purpose, as they include quantum effects, without limitations first-order perturbative approaches, also allowing taking into account more than two electronic states at once. However, huge computational demands QD methodologies, especially large molecules, currently limit their use a standard tool. To address problem, we here employ strategy that allows us almost whole set vibrational coordinates by selecting key elements Hilbert space significantly impact dynamics, thereby hugely reducing burden. Application protocol relatively INVEST reveals internal conversion in systems fast, making indirect emissive possible channel population S1 state. More importantly, study demonstrates dynamics can be accurately described reduced space, yield accurate few minutes time.

Language: Английский

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Nonradiative Spin-Forbidden Decay Processes in π- and Multiresonance-Acceptor-Based TADF Molecules

The Journal of Physical Chemistry C, Journal Year: 2024, Volume and Issue: 128(40), P. 16879 - 16891

Published: Oct. 1, 2024

Language: Английский

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Modeling MR-TADF Emitters: Excited-State Decay Rate Constants and Wave Function Descriptors

The Journal of Physical Chemistry C, Journal Year: 2024, Volume and Issue: 128(43), P. 18170 - 18181

Published: Oct. 17, 2024

Multiresonance thermally activated delayed fluorescence (MR-TADF) emitters have gained popularity given their potential of attaining negligible singlet–triplet energy gaps, i.e., ΔEST, without hindering emission, thus increasing the reverse and direct intersystem crossing rates affecting fluorescence. This is achieved due to singlet triplet states' short-range charge transfer character (SRCT). Thus, obtaining quantitative information about SRCT would help develop new MR-TADF emitters. work studies three different families emitters: DOBOA, DiKTa, OQAO. First, we compute adiabatic ΔEST with four methods (TDA-CAM-B3LYP, STEOM-DLPNO-CCSD, ADC(2), SCS-CC2). Then, (kr), (kISC), rate constants. For kr, assessed effect levels approximations on calculations. We show that kr does not depend significantly harmonic models (adiabatic Hessian or vertical Hessian), coordinate systems, broadening widths. Moreover, Herzberg–Teller effects are for but main contribution kISC kRISC. The computed constants agree well experimental results. propose use two wave function descriptors, Qat LOCa, based 1-particle transition density matrix, which assigns amount centered atoms. these descriptors transitions: S0 → S1, T1, S1 T1. studied cases, independent choice electronic structure method optimal geometry. decreases increase T1 Qat, while increases an Qat. These trends showcase how values can act as guiding design small values.

Language: Английский

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