Effects of donor position and multiple charge transfer pathways in asymmetric pyridyl-sulfonyl TADF emitters

Haykır, Gülçin; Aydemir, Murat; Tekin, Adem; Tekin, Emine; Danos, Andrew; Yüksel, Fatma; Hızal, Gürkan; Monkman, Andrew P.; Türksoy, Figen

doi:10.1016/j.mtcomm.2022.103550

Cited by 3 publications

(3 citation statements)

References 58 publications

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Section: Introductionmentioning

confidence: 99%

“…Surprisingly, the effect of the other key player in the equation, H SO , has been largely overlooked by the community as it is not as straightforward to investigate or engineer as the types of D and A subunits and their connectivity. [4][5][6][7][8][9][10][11][12][13][14] Alongside high efficiencies, one of the unique abilities of OLEDs compared to other lighting sources is the possibility of creating flexible devices; hence, alternative flexible anodes and substrates have attracted significant attention from OLED community in recent years. [15,16] ITO is the most common transparent anode for conventional OLEDs due to its superior optical and electrical properties.…”

Section: Introductionmentioning

confidence: 99%

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Rational Molecular Design Enables Efficient Blue TADF−OLEDs with Flexible Graphene Substrate

Sharif

Alemdar

Ozturk

et al. 2022

Adv Funct Materials

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Observation of thermally activated delayed fluorescence (TADF) in conjugated systems redefined the molecular design approach to realize highly efficient organic light emitting diodes (OLEDs) in the early 2010s. Enabling effective reverse intersystem crossing (RISC) by minimizing the difference between singlet and triplet excited state energies (ΔE ST ) is proven to be a widely applicable and fruitful approach, which results in remarkable external quantum efficiencies (EQE). The efficacy of RISC in these systems is mainly dictated by the first-order mixing coefficient (λ), which is proportional to spin-orbit coupling (H SO ) and inversely proportional to ΔE ST . While minimizing ΔE ST has been the focus of the OLED community over the last decade, the effect of H SO in these systems is largely overlooked. Here, molecular systems with increased H SO are designed and synthesized by substituting selected heteroatoms of high-performance TADF materials with heavy-atom selenium. A new series of multicolor TADF materials with remarkable EQEs are achieved. One of these materials, SeDF-B, results in pure blue emission with EQEs approaching 20%. Additionally, flexible graphene-based electrodes are developed for OLEDs and revealed to have similar performance as standard indium tin oxide (ITO) in most cases. These devices are the first report of TADF based OLEDs that utilize graphene-based anodes.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rational Molecular Design Enables Efficient Blue TADF−OLEDs with Flexible Graphene Substrate

Sharif

Alemdar

Ozturk

et al. 2022

Adv Funct Materials

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“…Previously, Kukhta et al have unraveled that an additional intramolecular dipole interaction restricts ortho-D-A dihedral angle rotation in DMAC-BZN positional isomers [60]. And the interconversion of triplets via the rISC mechanism is promoted when parallel carbazole (Cz) and phenothiazine (PTZ) charge transfer states are allowed to interact [61]. Recently, we demonstrated that electronic interaction between the donating moieties alters the local excited triplet ( 3 LE) energy and thus also ΔEST and TADF performance [62].…”

mentioning

confidence: 99%

Rational design of dibenzo[a,c]phenazine-derived isomeric thermally activated delayed fluorescence luminophores for efficient orange-red organic light-emitting diodes

Ye¹,

Yang²,

Stavrou³

et al. 2023

Dyes and Pigments

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3‐Ligated Phenothiazinyl‐terephthalonitrile Dyads and Triads ‐ Synthesis, Electronic Properties, Delayed Fluorescence and Electronic Structure

Kloeters

Meißner

Presser

et al. 2023

Chemistry A European J

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The bromine-lithium exchange-borylation-Suzuki sequence efficiently furnishes phenothiazine-terephthalonitrile donor-acceptor dyads and triads in high yields. In contrast to most phenothiazine-acceptor conjugates the title compounds are ligated in p-position to the phenothiazine nitrogen atom. Moreover, the acceptors are either directly linked or ligated by an arylene bridge and p-anisyl Nsubstituents on the phenothiazine are chosen to lock the tricycle into an intra-configuration. Cyclic voltammetry reveals effects of bridging and ligation of the N-substituent. Optical spectroscopy likewise displays similar band gaps, large Stokes shifts and substantial to high quantum yields in solution, in the solid state and in PMMA matrix. Time-resolved fluorescence spectroscopy indicates quite long fluorescence decay times in solution and emission components in the microsecond time range. TADF properties are further assessed by fluorescence increase in deoxygenated solution, gated emission spectroscopy and temperature-dependent determination of phosphorescence. The nature of the electronically excited states is investigated by DFT/MRCI. While for the directly ligated dyad a singlet-triplet energy gap ΔE ðS 1 À T 1 Þ of 0.24 eV can be estimated and is consistently confirmed by quantum chemical calculations on the lowest energy conformer, even lower DE ðS 1 À T 1 Þ of 0.029 and 0.008 eV are estimated for the investigated dyads and the triad in the solid state and in PMMA matrix.

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Effects of donor position and multiple charge transfer pathways in asymmetric pyridyl-sulfonyl TADF emitters

Cited by 3 publications

References 58 publications

Rational Molecular Design Enables Efficient Blue TADF−OLEDs with Flexible Graphene Substrate

Rational Molecular Design Enables Efficient Blue TADF−OLEDs with Flexible Graphene Substrate

Rational design of dibenzo[a,c]phenazine-derived isomeric thermally activated delayed fluorescence luminophores for efficient orange-red organic light-emitting diodes

3‐Ligated Phenothiazinyl‐terephthalonitrile Dyads and Triads ‐ Synthesis, Electronic Properties, Delayed Fluorescence and Electronic Structure

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