Azaborine as a Versatile Weak Donor for Thermally Activated Delayed Fluorescence (2023)
Journal Article
Sudhakar, P., Kuila, S., Stavrou, K., Danos, A., Slawin, A. M., Monkman, A., & Zysman-Colman, E. (2023). Azaborine as a Versatile Weak Donor for Thermally Activated Delayed Fluorescence. ACS Applied Materials and Interfaces, 15(21), 25806-25818. https://doi.org/10.1021/acsami.3c05409

Extensive research has been devoted to the development of thermally activated delayed fluorescence emitters, especially those showing pure-blue emission for use in lighting and fullcolor display applications. Towards that goal, herein we report a nov... Read More about Azaborine as a Versatile Weak Donor for Thermally Activated Delayed Fluorescence.

Balanced Energy Gaps as a Key Design Rule for Solution‐Phase Organic Room Temperature Phosphorescence (2023)
Journal Article
Paredis, S., Cardeynaels, T., Kuila, S., Deckers, J., Van Landeghem, M., Vandewal, K., …Maes, W. (2023). Balanced Energy Gaps as a Key Design Rule for Solution‐Phase Organic Room Temperature Phosphorescence. Chemistry - A European Journal, https://doi.org/10.1002/chem.202301369

Metal-free organic emitters that display solution-phase room temperature phosphorescence (sRTP) remain exceedingly rare. Here, we investigate the structural and photophysical properties that support sRTP by comparing a recently reported sRTP compound... Read More about Balanced Energy Gaps as a Key Design Rule for Solution‐Phase Organic Room Temperature Phosphorescence.

Donor, Acceptor, and Molecular Charge Transfer Emission All in One Molecule (2023)
Journal Article
Franca, L. G., Danos, A., & Monkman, A. (2023). Donor, Acceptor, and Molecular Charge Transfer Emission All in One Molecule. Journal of Physical Chemistry Letters, 14(11), 2764-2771. https://doi.org/10.1021/acs.jpclett.2c03925

The molecular photophysics in the thermally activated delayed fluorescence (TADF) spiro-acridine–anthracenone compound, ACRSA, is dominated by the rigid orthogonal spirocarbon bridging bond between the donor and acceptor. This critically decouples th... Read More about Donor, Acceptor, and Molecular Charge Transfer Emission All in One Molecule.

Rupturing aromaticity by periphery overcrowding (2023)
Journal Article
Saha, P. K., Mallick, A., Turley, A. T., Bismillah, A. N., Danos, A., Monkman, A. P., …McGonigal, P. R. (2023). Rupturing aromaticity by periphery overcrowding. Nature Chemistry, 15(4), 516-525. https://doi.org/10.1038/s41557-023-01149-6

The balance between strain relief and aromatic stabilization dictates the form and function of non-planar π-aromatics. Overcrowded systems are known to undergo geometric deformations, but the energetically favourable π-electron delocalization of thei... Read More about Rupturing aromaticity by periphery overcrowding.

Rational Molecular Design Enables Efficient Blue TADF−OLEDs with Flexible Graphene Substrate (2022)
Journal Article
Sharif, P., Alemdar, E., Ozturk, S., Caylan, O., Haciefendioglu, T., Buke, G., …Oral, A. (2022). Rational Molecular Design Enables Efficient Blue TADF−OLEDs with Flexible Graphene Substrate. Advanced Functional Materials, 32(47), Article 2207324. https://doi.org/10.1002/adfm.202207324

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... Read More about Rational Molecular Design Enables Efficient Blue TADF−OLEDs with Flexible Graphene Substrate.

Intramolecular Hydrogen Bonding in Thermally Activated Delayed Fluorescence Emitters: Is There Evidence Beyond Reasonable Doubt? (2022)
Journal Article
Hempe, M., Kukhta, N. A., Danos, A., Batsanov, A. S., Monkman, A. P., & Bryce, M. R. (2022). Intramolecular Hydrogen Bonding in Thermally Activated Delayed Fluorescence Emitters: Is There Evidence Beyond Reasonable Doubt?. Journal of Physical Chemistry Letters, 13(35), 8221-8227. https://doi.org/10.1021/acs.jpclett.2c00907

Intramolecular hydrogen bonding between donor and acceptor segments in thermally activated delayed fluorescence (TADF) materials is now frequently employed to─purportedly─rigidify the structure and improve the emission performance of these materials.... Read More about Intramolecular Hydrogen Bonding in Thermally Activated Delayed Fluorescence Emitters: Is There Evidence Beyond Reasonable Doubt?.

Laplace Transform Fitting as a Tool To Uncover Distributions of Reverse Intersystem Crossing Rates in TADF Systems (2022)
Journal Article
Kelly, D., Gomes Franca, L., Stavrou, K., Danos, A., & Monkman, A. P. (2022). Laplace Transform Fitting as a Tool To Uncover Distributions of Reverse Intersystem Crossing Rates in TADF Systems. Journal of Physical Chemistry Letters, 13(30), 6981-6986. https://doi.org/10.1021/acs.jpclett.2c01864

Donor–acceptor (D–A) thermally activated delayed fluorescence (TADF) molecules are exquisitely sensitive to D–A dihedral angle. Although commonly simplified to an average value, these D–A angles nonetheless exist as distributions across the individua... Read More about Laplace Transform Fitting as a Tool To Uncover Distributions of Reverse Intersystem Crossing Rates in TADF Systems.

Novel D–A chromophores with condensed 1,2,4-triazine system simultaneously display thermally activated delayed fluorescence and crystallization-induced phosphorescence (2022)
Journal Article
Maggiore, A., Tan, X., Brosseau, A., Danos, A., Miomandre, F., Monkman, A. P., …Clavier, G. (2022). Novel D–A chromophores with condensed 1,2,4-triazine system simultaneously display thermally activated delayed fluorescence and crystallization-induced phosphorescence. Physical Chemistry Chemical Physics, 24(29), 17770-17781. https://doi.org/10.1039/d2cp00777k

Control of photophysical properties is crucial for the continued development of electroluminescent devices and luminescent materials. Preparation and study of original molecules uncovers design rules towards efficient materials and devices. Here we h... Read More about Novel D–A chromophores with condensed 1,2,4-triazine system simultaneously display thermally activated delayed fluorescence and crystallization-induced phosphorescence.

Emission and Absorption Tuning in TADF B,N‐Doped Heptacenes: Toward Ideal‐Blue Hyperfluorescent OLEDs (2022)
Journal Article
Stavrou, K., Madayanad Suresh, S., Hall, D., Danos, A., Kukhta, N. A., Slawin, A. M., …Zysman‐Colman, E. (2022). Emission and Absorption Tuning in TADF B,N‐Doped Heptacenes: Toward Ideal‐Blue Hyperfluorescent OLEDs. Advanced Optical Materials, 10(17), Article 2200688. https://doi.org/10.1002/adom.202200688

Developing high-efficiency purely organic blue organic light-emitting diodes (OLEDs) that meet the stringent industry standards is a major current research challenge. Hyperfluorescent device approaches achieve in large measure the desired high perfor... Read More about Emission and Absorption Tuning in TADF B,N‐Doped Heptacenes: Toward Ideal‐Blue Hyperfluorescent OLEDs.

Effects of donor position and multiple charge transfer pathways in asymmetric pyridyl-sulfonyl TADF emitters (2022)
Journal Article
Haykir, G., Aydemir, M., Tekin, A., Tekin, E., Danos, A., Yuksel, F., …Turksoy, F. (2022). Effects of donor position and multiple charge transfer pathways in asymmetric pyridyl-sulfonyl TADF emitters. Materials Today Communications, 31, Article 103550. https://doi.org/10.1016/j.mtcomm.2022.103550

We have designed and synthesized a pair of highly asymmetric D-aA-D′ type pyridyl-sulfonyl based isomers comprising phenothiazine (PTZ) and carbazole (Cz) donor units, which are able to emit thermally activated delayed fluorescence. PTZ-pS4-Py-2Cz an... Read More about Effects of donor position and multiple charge transfer pathways in asymmetric pyridyl-sulfonyl TADF emitters.

Extended Conjugation Attenuates the Quenching of Aggregation-Induced Emitters by Photocyclization Pathways (2022)
Journal Article
Turley, A., Saha, P., Danos, A., Bismillah, A., Monkman, A., Yufit, D., …McGonigal, P. (2022). Extended Conjugation Attenuates the Quenching of Aggregation-Induced Emitters by Photocyclization Pathways. Angewandte Chemie International Edition, 61(24), Article e202202193. https://doi.org/10.1002/anie.202202193

Herein, we expose how the antagonistic relationship between solid-state luminescence and photocyclization of oligoaryl alkenes chromophores is modulated by the conjugation length of their alkenyl backbones. Heptaaryl cycloheptatriene molecular rotors... Read More about Extended Conjugation Attenuates the Quenching of Aggregation-Induced Emitters by Photocyclization Pathways.

The Effect of Imide Substituents on the Excited State Properties of Perylene Diimide Derivatives (2022)
Journal Article
Aksoy, E., Danos, A., Li, C., Monkman, A., & Varlikli, C. (2022). The Effect of Imide Substituents on the Excited State Properties of Perylene Diimide Derivatives. Turkish journal of science and technology, 17(1), 11-21. https://doi.org/10.55525/tjst.952823

Solid state optical properties of fluorescent materials are important for many photonic devices such as organic light emitting diodes, frequency down-converters or luminescent solar concentrators. Perylene diimides (PDIs) represent one of the most po... Read More about The Effect of Imide Substituents on the Excited State Properties of Perylene Diimide Derivatives.

Determining non-radiative decay rates in TADF compounds using coupled transient and steady state optical data (2022)
Journal Article
Sem, S., Jenatsch, S., Stavrou, K., Danos, A., Monkman, A. P., & Ruhstaller, B. (2022). Determining non-radiative decay rates in TADF compounds using coupled transient and steady state optical data. Journal of Materials Chemistry C Materials for optical and electronic devices, 10(12), 4878-4885. https://doi.org/10.1039/d1tc05594a

Thermally-activated delayed fluorescence (TADF) compounds are promising materials used in emissive layers of organic light-emitting diodes (OLEDs). Their main benefit is that they allow the internal quantum efficiency of the OLED to reach up to 100%... Read More about Determining non-radiative decay rates in TADF compounds using coupled transient and steady state optical data.

Diindolocarbazole – achieving multiresonant thermally activated delayed fluorescence without the need for acceptor units (2022)
Journal Article
Hall, D., Stavrou, K., Duda, E., Danos, A., Bagnich, S., Warriner, S., …Zysman-Colman, E. (2022). Diindolocarbazole – achieving multiresonant thermally activated delayed fluorescence without the need for acceptor units. Materials Horizons, 9(3), 1068-1080. https://doi.org/10.1039/d1mh01383a

In this work we present a new multi-resonance thermally activated delayed fluorescence (MR-TADF) emitter paradigm, demonstrating that the structure need not require the presence of acceptor atoms. Based on an in silico design, the compound DiICzMes4... Read More about Diindolocarbazole – achieving multiresonant thermally activated delayed fluorescence without the need for acceptor units.

Bridge control of photophysical properties in benzothiazole-phenoxazine emitters – from thermally activated delayed fluorescence to room temperature phosphorescence (2022)
Journal Article
Paredis, S., Cardeynaels, T., Deckers, J., Danos, A., Vanderzande, D., Monkman, A. P., …Maes, W. (2022). Bridge control of photophysical properties in benzothiazole-phenoxazine emitters – from thermally activated delayed fluorescence to room temperature phosphorescence. Journal of Materials Chemistry C Materials for optical and electronic devices, 10(12), 4775-4784. https://doi.org/10.1039/d1tc04885f

The bridging phenyl group in a fluorescent phenoxazine-benzothiazole donor–acceptor dyad is replaced by either a naphthalene or a thiophene moiety to probe the influence of a more extended conjugated system or the presence of a sulfur-containing hete... Read More about Bridge control of photophysical properties in benzothiazole-phenoxazine emitters – from thermally activated delayed fluorescence to room temperature phosphorescence.

Spiro donor–acceptor TADF emitters: naked TADF free from inhomogeneity caused by donor acceptor bridge bond disorder. Fast rISC and invariant photophysics in solid state hosts (2022)
Journal Article
Gomes Franca, L., Danos, A., & Monkman, A. (2022). Spiro donor–acceptor TADF emitters: naked TADF free from inhomogeneity caused by donor acceptor bridge bond disorder. Fast rISC and invariant photophysics in solid state hosts. Journal of Materials Chemistry C Materials for optical and electronic devices, 10(4), 1313-1325. https://doi.org/10.1039/d1tc04484b

We have studied the thermally activated delayed fluorescence (TADF) properties of the spiro-bridged donor–acceptor molecule, 10-phenyl-10H,10′H-spiro[acridine-9,9-anthracen]-10′-one, (ACRSA) in guest–host films and used it as a probe to explore the d... Read More about Spiro donor–acceptor TADF emitters: naked TADF free from inhomogeneity caused by donor acceptor bridge bond disorder. Fast rISC and invariant photophysics in solid state hosts.

Effects of asymmetric acceptor and donor positioning in deep blue pyridyl-sulfonyl based TADF emitters (2021)
Journal Article
Haykir, G., Aydemir, M., Danos, A., Gumus, S., Hizal, G., Monkman, A. P., & Turksoy, F. (2021). Effects of asymmetric acceptor and donor positioning in deep blue pyridyl-sulfonyl based TADF emitters. Dyes and Pigments, 194, Article 109579. https://doi.org/10.1016/j.dyepig.2021.109579

In this work, we report synthesis and photophysical properties of deep-blue emitting donor-acceptor (D-A) and donor-acceptor-donor (D-A-D) thermally activated delayed fluorescence (TADF) molecules, where the molecules designed using carbazole as a do... Read More about Effects of asymmetric acceptor and donor positioning in deep blue pyridyl-sulfonyl based TADF emitters.

Silylethynyl Substitution for Preventing Aggregate Formation in Perylene Diimides (2021)
Journal Article
Aksoy, E., Danos, A., Li, C., Monkman, A. P., & Varlikli, C. (2021). Silylethynyl Substitution for Preventing Aggregate Formation in Perylene Diimides. Journal of Physical Chemistry C, 125(23), 13041-13049. https://doi.org/10.1021/acs.jpcc.1c03131

Ethynylene-bridged perylene diimides (PDIs) with different sized silane groups have been synthesized as a steric blocking group to prevent the formation of non-radiative trap sites, for example, strong H-aggregates and other dimers or excimers. Excit... Read More about Silylethynyl Substitution for Preventing Aggregate Formation in Perylene Diimides.

Vibrational Damping Reveals Vibronic Coupling in Thermally Activated Delayed Fluorescence Materials (2021)
Journal Article
Hempe, M., Kukhta, N. A., Danos, A., Fox, M. A., Batsanov, A. S., Monkman, A. P., & Bryce, M. R. (2021). Vibrational Damping Reveals Vibronic Coupling in Thermally Activated Delayed Fluorescence Materials. Chemistry of Materials, 33(9), 3066-3080. https://doi.org/10.1021/acs.chemmater.0c03783

We investigate a series of D–A molecules consisting of spiro[acridan-9,9′-fluorene] as the donor and 2-phenylenepyrimidine as the acceptor. In two of the materials, a spiro center effectively electronically isolates the D unit from (consequently) opt... Read More about Vibrational Damping Reveals Vibronic Coupling in Thermally Activated Delayed Fluorescence Materials.

Are the Rates of Dexter Transfer in TADF Hyperfluorescence Systems Optically Accessible? (2021)
Journal Article
Haase, N., Danos, A., Pflumm, C., Stachelek, P., Brütting, W., & Monkman, A. P. (2021). Are the Rates of Dexter Transfer in TADF Hyperfluorescence Systems Optically Accessible?. Materials Horizons, 8(6), 1805-1815. https://doi.org/10.1039/d0mh01666g

Seemingly not, but for unexpected reasons. Combining the triplet harvesting properties of TADF materials with the fast emission rates and colour purity of fluorescent emitters is attractive for developing high performance OLEDs. In this “hyperfluores... Read More about Are the Rates of Dexter Transfer in TADF Hyperfluorescence Systems Optically Accessible?.