Dataset Information

Triazatruxene: A Rigid Central Donor Unit for a D-A₃ Thermally Activated Delayed Fluorescence Material Exhibiting Sub-Microsecond Reverse Intersystem Crossing and Unity Quantum Yield via Multiple Singlet-Triplet State Pairs.

ABSTRACT: By inverting the common structural motif of thermally activated delayed fluorescence materials to a rigid donor core and multiple peripheral acceptors, reverse intersystem crossing (rISC) rates are demonstrated in an organic material that enables utilization of triplet excited states at faster rates than Ir-based phosphorescent materials. A combination of the inverted structure and multiple donor-acceptor interactions yields up to 30 vibronically coupled singlet and triplet states within 0.2 eV that are involved in rISC. This gives a significant enhancement to the rISC rate, leading to delayed fluorescence decay times as low as 103.9 ns. This new material also has an emission quantum yield ≈1 and a very small singlet-triplet gap. This work shows that it is possible to achieve both high photoluminescence quantum yield and fast rISC in the same molecule. Green organic light-emitting diode devices with external quantum efficiency >30% are demonstrated at 76 cd m^-2.

SUBMITTER: Dos Santos PL

PROVIDER: S-EPMC6010696 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Publications

Triazatruxene: A Rigid Central Donor Unit for a D-A<sub>3</sub> Thermally Activated Delayed Fluorescence Material Exhibiting Sub-Microsecond Reverse Intersystem Crossing and Unity Quantum Yield via Multiple Singlet-Triplet State Pairs.

Dos Santos Paloma L PL Ward Jonathan S JS Congrave Daniel G DG Batsanov Andrei S AS Eng Julien J Stacey Jessica E JE Penfold Thomas J TJ Monkman Andrew P AP Bryce Martin R MR

Advanced science (Weinheim, Baden-Wurttemberg, Germany) 20180416 6

By inverting the common structural motif of thermally activated delayed fluorescence materials to a rigid donor core and multiple peripheral acceptors, reverse intersystem crossing (rISC) rates are demonstrated in an organic material that enables utilization of triplet excited states at faster rates than Ir-based phosphorescent materials. A combination of the inverted structure and multiple donor-acceptor interactions yields up to 30 vibronically coupled singlet and triplet states within 0.2 eV ...[more]

PMID: 29938177

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Project description:Owing to their exceptional photophysical properties and high photostability, perylene diimide (PDI) chromophores have found various applications as building blocks of materials for organic electronics. In many light-induced processes in PDI derivatives, chromophore excited states with high spin multiplicities, such as triplet or quintet states, have been revealed as key intermediates. The exploration of their properties and formation conditions is thus expected to provide invaluable insight into their underlying photophysics and promises to reveal strategies for increasing the performance of optoelectronic devices. However, accessing these high-multiplicity excited states of PDI to increase our mechanistic understanding remains a difficult task, due to the fact that the lowest excited singlet state of PDI decays with near-unity quantum yield to its ground state. Here we make use of radical-enhanced intersystem crossing (EISC) to generate the PDI triplet state in high yield. One or two 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) stable radicals were covalently attached to the imide position of PDI chromophores with and without p-tert-butylphenoxy core substituents. By combining femtosecond UV-vis transient absorption and transient electron paramagnetic resonance spectroscopies, we demonstrate strong magnetic exchange coupling between the PDI triplet state and TEMPO, resulting in the formation of excited quartet or quintet states. Important differences in the S1 state deactivation rate constants and triplet yields are observed for compounds bearing PDI moieties with different core substitution patterns. We show that these differences can be rationalized by considering the varying importance of competitive excited state decay processes, such as electron and excitation energy transfer. The comparison of the results obtained for different PDI-TEMPO derivatives leads us to propose design guidelines for optimizing the efficiency of triplet sensitization in molecular assemblies by EISC.

Dataset Information

Triazatruxene: A Rigid Central Donor Unit for a D-A₃ Thermally Activated Delayed Fluorescence Material Exhibiting Sub-Microsecond Reverse Intersystem Crossing and Unity Quantum Yield via Multiple Singlet-Triplet State Pairs.

Publications

Triazatruxene: A Rigid Central Donor Unit for a D-A<sub>3</sub> Thermally Activated Delayed Fluorescence Material Exhibiting Sub-Microsecond Reverse Intersystem Crossing and Unity Quantum Yield via Multiple Singlet-Triplet State Pairs.

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Dataset Information

Triazatruxene: A Rigid Central Donor Unit for a D-A3 Thermally Activated Delayed Fluorescence Material Exhibiting Sub-Microsecond Reverse Intersystem Crossing and Unity Quantum Yield via Multiple Singlet-Triplet State Pairs.

Publications

Triazatruxene: A Rigid Central Donor Unit for a D-A<sub>3</sub> Thermally Activated Delayed Fluorescence Material Exhibiting Sub-Microsecond Reverse Intersystem Crossing and Unity Quantum Yield via Multiple Singlet-Triplet State Pairs.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Triazatruxene: A Rigid Central Donor Unit for a D-A₃ Thermally Activated Delayed Fluorescence Material Exhibiting Sub-Microsecond Reverse Intersystem Crossing and Unity Quantum Yield via Multiple Singlet-Triplet State Pairs.