From Phosphorescence to Delayed Fluorescence in One Step: Tuning Photophysical Properties by Quaternisation of an sp2-Hybridised Nitrogen Atom (2022)
Journal Article
Klimash, A., Prlj, A., Yufit, D., Mallick, A., Curchod, B., McGonigal, P., …Etherington, M. (2022). From Phosphorescence to Delayed Fluorescence in One Step: Tuning Photophysical Properties by Quaternisation of an sp2-Hybridised Nitrogen Atom. Journal of Materials Chemistry C Materials for optical and electronic devices, 10(25), 9484-9491. https://doi.org/10.1039/d2tc01737g

Control of the delayed emission of organic compounds is an important factor in the development of new display technology and for the emerging use of organic emitters in sensing and fluorescence microscopy. In particular, there is a need to understand... Read More about From Phosphorescence to Delayed Fluorescence in One Step: Tuning Photophysical Properties by Quaternisation of an sp2-Hybridised Nitrogen Atom.

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.

Dominant dimer emission provides colour stability for red thermally activated delayed fluorescence emitter (2022)
Journal Article
Cardeynaels, T., Etherington, M. K., Paredis, S., Batsanov, A. S., Deckers, J., Stavrou, K., …Maes, W. (2022). Dominant dimer emission provides colour stability for red thermally activated delayed fluorescence emitter. Journal of Materials Chemistry C Materials for optical and electronic devices, 10(15), https://doi.org/10.1039/d1tc04913e

Colour purity and stability in multi-donor thermally activated delayed fluorescence (TADF) emitters has significant implications for commercial organic light-emitting diode (OLED) design. The formation of emissive dimer states in the well-known 1,2,3... Read More about Dominant dimer emission provides colour stability for red thermally activated delayed fluorescence emitter.

Suppressing Dimer Formation by Increasing Conformational Freedom in Multi-Carbazole Thermally Activated Delayed Fluorescence Emitters (2020)
Journal Article
Salah, L., Etherington, M., Shuaib, A., Danos, A., Nazeer, A., Ghazal, B., …Makhseed, S. (2021). Suppressing Dimer Formation by Increasing Conformational Freedom in Multi-Carbazole Thermally Activated Delayed Fluorescence Emitters. Journal of Materials Chemistry C Materials for optical and electronic devices, 9(1), 189-198. https://doi.org/10.1039/d0tc04222f

Ideal emitters for organic light-emitting diodes (OLEDs) are capable of efficiently harvesting non-emissive triplet states, have high colour stabilities, and possess high photoluminescence quantum yields (PLQYs). Maintaining colour stability and PLQY... Read More about Suppressing Dimer Formation by Increasing Conformational Freedom in Multi-Carbazole Thermally Activated Delayed Fluorescence Emitters.

Investigation of Thermally Activated Delayed Fluorescence from a Donor–Acceptor Compound with Time-Resolved Fluorescence and Density Functional Theory Applying an Optimally Tuned Range-Separated Hybrid Functional (2020)
Journal Article
Scholz, R., Kleine, P., Lygaitis, R., Popp, L., Lenk, S., Etherington, M. K., …Reineke, S. (2020). Investigation of Thermally Activated Delayed Fluorescence from a Donor–Acceptor Compound with Time-Resolved Fluorescence and Density Functional Theory Applying an Optimally Tuned Range-Separated Hybrid Functional. The Journal of Physical Chemistry A, 124(8), 1535-1553. https://doi.org/10.1021/acs.jpca.9b11083

Emitters showing thermally activated delayed fluorescence (TADF) in electroluminescent devices rely on efficient reverse intersystem crossing (rISC) arising from small thermal activation barriers between the lowest excited triplet and singlet manifol... Read More about Investigation of Thermally Activated Delayed Fluorescence from a Donor–Acceptor Compound with Time-Resolved Fluorescence and Density Functional Theory Applying an Optimally Tuned Range-Separated Hybrid Functional.

Revealing Resonance Effects and Intramolecular Dipole Interactions in the Positional Isomers of Benzonitrile-Core Thermally Activated Delayed Fluorescence Materials (2019)
Journal Article
Kukhta, N., Higginbotham, H., Matulaitis, T., Danos, A., Bismillah, A., Haase, N., …Monkman, A. (2019). Revealing Resonance Effects and Intramolecular Dipole Interactions in the Positional Isomers of Benzonitrile-Core Thermally Activated Delayed Fluorescence Materials. Journal of Materials Chemistry C Materials for optical and electronic devices, 7(30), 9184-9194. https://doi.org/10.1039/c9tc02742d

We report on the properties of the three positional isomers of (2,7-di-tert-butyl-9,9-dimethylacridin-10(9H)-yl)benzonitrile, which are found to have comparable donor steric environments and donor–acceptor dihedral angles. An unexpected intramolecula... Read More about Revealing Resonance Effects and Intramolecular Dipole Interactions in the Positional Isomers of Benzonitrile-Core Thermally Activated Delayed Fluorescence Materials.

Intramolecular Dimerization Quenching of Delayed Emission in Asymmetric D-D’-A TADF Emitters (2019)
Journal Article
Woon, K. L., Yi, C., Pan, K., Etherington, M. K., Wu, C., Wong, K., & Monkman, A. P. (2019). Intramolecular Dimerization Quenching of Delayed Emission in Asymmetric D-D’-A TADF Emitters. Journal of Physical Chemistry C, 123(19), 12400-12410. https://doi.org/10.1021/acs.jpcc.9b01900

Understanding the excited-state dynamics and conformational relaxation in thermallyactivated delayed fluorescence (TADF) molecules, including conformations that potentially support intramolecular through-space charge transfer, can open new avenues fo... Read More about Intramolecular Dimerization Quenching of Delayed Emission in Asymmetric D-D’-A TADF Emitters.

Persistent Dimer Emission in Thermally Activated Delayed Fluorescence Materials (2019)
Journal Article
Etherington, M. K., Kukhta, N. A., Higginbotham, H. F., Danos, A., Bismillah, A. N., Graves, D. R., …Monkman, A. P. (2019). Persistent Dimer Emission in Thermally Activated Delayed Fluorescence Materials. Journal of Physical Chemistry C, 123(17), 11109-11117. https://doi.org/10.1021/acs.jpcc.9b01458

We expose significant changes in emission color of carbazole-based thermally activated delayed fluorescence (TADF) emitters that arise through the presence of persistent dimer states in thin films and organic light-emitting diodes(OLEDs). Direct phot... Read More about Persistent Dimer Emission in Thermally Activated Delayed Fluorescence Materials.

Thermally Activated Delayed Fluorescence Mediated through the Upper Triplet State Manifold in Non-Charge-Transfer Star-Shaped Triphenylamine–Carbazole Molecules (2018)
Journal Article
Pander, P., Motyka, R., Zassowski, P., Etherington, M. K., Varsano, D., da Silva, T. J., …Monkman, A. P. (2018). Thermally Activated Delayed Fluorescence Mediated through the Upper Triplet State Manifold in Non-Charge-Transfer Star-Shaped Triphenylamine–Carbazole Molecules. Journal of Physical Chemistry C, 122(42), 23934-23942. https://doi.org/10.1021/acs.jpcc.8b07610

Thermally activated delayed fluorescence has been found in a group of tricarbazolylamines that are purely electron-donating, non-charge-transfer (CT) molecules. We show that the reverse intersystem crossing step in these materials is mediated through... Read More about Thermally Activated Delayed Fluorescence Mediated through the Upper Triplet State Manifold in Non-Charge-Transfer Star-Shaped Triphenylamine–Carbazole Molecules.

Chemical and conformational control of the energy gaps involved in the thermally activated delayed fluorescence mechanism (2018)
Journal Article
dos Santos, P. L., Etherington, M. K., & Monkman, A. P. (2018). Chemical and conformational control of the energy gaps involved in the thermally activated delayed fluorescence mechanism. Journal of Materials Chemistry C Materials for optical and electronic devices, 6(18), 4842-4853. https://doi.org/10.1039/c8tc00991k

This review summarises the significant developments in our understanding and control of thermally-activated delayed fluorescence (TADF) molecules and the spin–vibronic coupling mechanism, from which we have designed new generations of emitters. It co... Read More about Chemical and conformational control of the energy gaps involved in the thermally activated delayed fluorescence mechanism.

Excited-State Aromatic Interactions in the Aggregation-Induced Emission of Molecular Rotors (2017)
Journal Article
Sturala, J., Etherington, M. K., Bismillah, A. N., Higginbotham, H. F., Trewby, W. J., Aguilar, J. A., …McGonigal, P. R. (2017). Excited-State Aromatic Interactions in the Aggregation-Induced Emission of Molecular Rotors. Journal of the American Chemical Society, 139(49), 17882-17889. https://doi.org/10.1021/jacs.7b08570

Small, apolar aromatic groups, such as phenyl rings, are commonly included in the structures of fluorophores in order to impart hindered intramolecular rotations, leading to desirable solid-state luminescence properties. However, they are not normall... Read More about Excited-State Aromatic Interactions in the Aggregation-Induced Emission of Molecular Rotors.

Fluorescence and Phosphorescence Anisotropy from Oriented Films of Thermally Activated Delayed Fluorescence Emitters (2017)
Journal Article
Higginbotham, H. F., Etherington, M. K., & Monkman, A. P. (2017). Fluorescence and Phosphorescence Anisotropy from Oriented Films of Thermally Activated Delayed Fluorescence Emitters. Journal of Physical Chemistry Letters, https://doi.org/10.1021/acs.jpclett.7b00729

Anisotropy within three TADF materials has been observed using steady-state fluorescence polarisation. This technique has allowed for the observation of differences in polarisation within dilute solution, and both un-stretched and stretched films; th... Read More about Fluorescence and Phosphorescence Anisotropy from Oriented Films of Thermally Activated Delayed Fluorescence Emitters.

The Contributions of Molecular Vibrations and Higher Triplet Levels to the Intersystem Crossing Mechanism in Metal-Free Organic Emitters (2017)
Journal Article
Huang, R., Avó, J., Northey, T., Chaning-Pearce, E., dos Santos, P. L., Ward, J. S., …Dias, F. B. (2017). The Contributions of Molecular Vibrations and Higher Triplet Levels to the Intersystem Crossing Mechanism in Metal-Free Organic Emitters. Journal of Materials Chemistry C Materials for optical and electronic devices, 5(25), 6269-6280. https://doi.org/10.1039/c7tc01958k

Intense, simultaneous, room temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) is observed in a series of donor-acceptor-donor (D–A–D) molecules. This dual-luminescence is stronger in the “angular” isomers, compared... Read More about The Contributions of Molecular Vibrations and Higher Triplet Levels to the Intersystem Crossing Mechanism in Metal-Free Organic Emitters.

Regio- and conformational isomerization critical to design of efficient thermally-activated delayed fluorescence emitters (2017)
Journal Article
Etherington, M. K., Franchello, F., Gibson, J., Northey, T., Santos, J., Ward, J. S., …Monkman, A. P. (2017). Regio- and conformational isomerization critical to design of efficient thermally-activated delayed fluorescence emitters. Nature Communications, 8, Article 14987. https://doi.org/10.1038/ncomms14987

Regio- and conformational isomerization are fundamental in chemistry, with profound effects upon physical properties, however their role in excited state properties is less developed. Here two regioisomers of bis(10H-phenothiazin-10-yl)dibenzo[b,d]th... Read More about Regio- and conformational isomerization critical to design of efficient thermally-activated delayed fluorescence emitters.

Revealing the spin–vibronic coupling mechanism of thermally activated delayed fluorescence (2016)
Journal Article
Etherington, M. K., Gibson, J., Higginbotham, H. F., Penfold, T. J., & Monkman, A. P. (2016). Revealing the spin–vibronic coupling mechanism of thermally activated delayed fluorescence. Nature Communications, 7, Article 13680. https://doi.org/10.1038/ncomms13680

Knowing the underlying photophysics of thermally activated delayed fluorescence (TADF) allows proper design of high efficiency organic light-emitting diodes. We have proposed a model to describe reverse intersystem crossing (rISC) in donor–acceptor c... Read More about Revealing the spin–vibronic coupling mechanism of thermally activated delayed fluorescence.

Ultrahigh Efficiency Fluorescent Single and Bi-Layer Organic Light Emitting Diodes: The Key Role of Triplet Fusion (2012)
Journal Article
Chiang, C., Kimyonok, A., Etherington, M. K., Griffiths, G. C., Jankus, V., Turksoy, F., & Monkman, A. P. (2013). Ultrahigh Efficiency Fluorescent Single and Bi-Layer Organic Light Emitting Diodes: The Key Role of Triplet Fusion. Advanced Functional Materials, 23(6), 739-746. https://doi.org/10.1002/adfm.201201750

A new family of anthracene core, highly fluorescent emitters is synthesized which include diphenylamine hole transport end groups. Using a very simple one or two layer organic light emitting diode (OLED) structure, devices without outcoupling achieve... Read More about Ultrahigh Efficiency Fluorescent Single and Bi-Layer Organic Light Emitting Diodes: The Key Role of Triplet Fusion.