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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.

Less Is More: Dilution Enhances Optical and Electrical Performance of a TADF Exciplex (2019)
Journal Article
Colella, M., Danos, A., & Monkman, A. P. (2019). Less Is More: Dilution Enhances Optical and Electrical Performance of a TADF Exciplex. Journal of Physical Chemistry Letters, 10(4), 793-798. https://doi.org/10.1021/acs.jpclett.8b03646

A surprising yet highly practical approach to improve the performance of a TADF exciplex blend is reported. Using the TSBPA donor and PO-T2T acceptor to form an exciplex, we are able to blue shift the emission, increase PLQY from 58 to 80%, and incre... Read More about Less Is More: Dilution Enhances Optical and Electrical Performance of a TADF Exciplex.

Spontaneous emission enhancement in planar metal-organic structures (2018)
Journal Article
Morozov, K., Ivanov, K., Selenin, N., Mikhrin, S., Sa Pereira, D. D., Menelaou, C., …Kaliteevski, M. (2018). Spontaneous emission enhancement in planar metal-organic structures. Journal of Physics: Conference Series, 1135, Article 012034. https://doi.org/10.1088/1742-6596/1135/1/012034

We provide an experimental investigation of a Purcell enhancement in a silver-organic periodic structure with an organic material CBP (4,4'-Bis(N-carbazolyl)-1,1'-biphenyl). Were fabricated two structures using a thermal evaporation technique with a... Read More about Spontaneous emission enhancement in planar metal-organic structures.

Purcell effect investigation in organic Tamm plasmon structures (2018)
Journal Article
Morozov, K., Ivanov, K., Selenin, N., Mikhrin, S., Sa Pereira, D. D., Menelaou, C., …Kaliteevski, M. (2018). Purcell effect investigation in organic Tamm plasmon structures. Journal of Physics: Conference Series, 1135, Article 012082. https://doi.org/10.1088/1742-6596/1135/1/012082

We provide a theoretical and experimental investigation of a Purcell enhancement in a Tamm-plasmon based microcavity structure with an organic (4,4'-Bis(N-carbazolyl)−l,l'- biphenyl (CBP)) active layer. The microcavity structure was fabricated using... Read More about Purcell effect investigation in organic Tamm plasmon structures.

Importance of Chromophore Rigidity on the Efficiency of Blue Thermally Activated Delayed Fluorescence Emitters (2018)
Journal Article
Kukhta, N. A., Batsanov, A. S., Bryce, M. R., & Monkman, A. P. (2018). Importance of Chromophore Rigidity on the Efficiency of Blue Thermally Activated Delayed Fluorescence Emitters. Journal of Physical Chemistry C, 122(50), 28564-28575. https://doi.org/10.1021/acs.jpcc.8b10867

Four new symmetrical donor–acceptor–donor (D–A–D)-type molecules are reported with diphenylamine (DPA) or 10,11-dihydro-5H-dibenz[b,f]azepine (Az) as electron donors and 9,9-dimethylthioxanthene-S,S-dioxide (TXO2) as the electron acceptor. The donors... Read More about Importance of Chromophore Rigidity on the Efficiency of Blue Thermally Activated Delayed Fluorescence Emitters.

Production and Characterization of Vacuum Deposited Organic Light Emitting Diodes (2018)
Journal Article
de Sa Pereira, D., Monkman, A. P., & Data, P. (2018). Production and Characterization of Vacuum Deposited Organic Light Emitting Diodes. Journal of Visualized Experiments, Article e56593. https://doi.org/10.3791/56593

A method for producing simple and efficient thermally-activated delayed fluorescence organic light-emitting diodes (OLEDs) based on guest-host or exciplex donor-acceptor emitters is presented. With a step-by-step procedure, readers will be able to re... Read More about Production and Characterization of Vacuum Deposited Organic Light Emitting Diodes.

Interfacial TADF Exciplex as a Tool to Localise Excitons, Improve Efficiency and Increase OLED Lifetime (2018)
Journal Article
Colella, M., Pander, P. H., Pereira, D. D. S., & Monkman, A. P. (2018). Interfacial TADF Exciplex as a Tool to Localise Excitons, Improve Efficiency and Increase OLED Lifetime. ACS Applied Materials and Interfaces, 10(46), 40001-40007. https://doi.org/10.1021/acsami.8b15942

In this work, we employ a TADF exciplex formed between the emissive layer (EML) host, 26DCzPPy, and the electron transport layer (ETL), PO-T2T at the interface between the EML and the ETL to improve the stability and efficiency of a phosphorescence O... Read More about Interfacial TADF Exciplex as a Tool to Localise Excitons, Improve Efficiency and Increase OLED Lifetime.

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.

Solution processable small molecule based TADF exciplex OLEDs (2018)
Journal Article
Colella, M., Pander, P., & Monkman, A. P. (2018). Solution processable small molecule based TADF exciplex OLEDs. Organic Electronics, 62, 168-173. https://doi.org/10.1016/j.orgel.2018.07.020

In this work we report the optimisation of the solution processable TADF exciplex emitter in OLED devices formed by the small molecules 9-[2,8]-9-carbazole-[dibenzothiophene-S,S-dioxide]-carbazole (DCz-DBTO2) and 4,4′-cyclohexylidenebis[N,N-bis(4-met... Read More about Solution processable small molecule based TADF exciplex OLEDs.

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.

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 (2018)
Journal Article
dos Santos, P. L., Ward, J. S., Congrave, D. G., Batsanov, A. S., Eng, J., Stacey, J. E., …Bryce, M. R. (2018). 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. Advanced Science, 5(6), Article 1700989. https://doi.org/10.1002/advs.201700989

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 uti... Read More about 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.

Effects of Ortho-Phenyl Substitution on the rISC Rate of D–A Type TADF Molecules (2018)
Journal Article
Higginbotham, H. F., Yi, C., Monkman, A. P., & Wong, K. (2018). Effects of Ortho-Phenyl Substitution on the rISC Rate of D–A Type TADF Molecules. Journal of Physical Chemistry C, 122(14), 7627-7634. https://doi.org/10.1021/acs.jpcc.8b01579

Two new donor (D)–acceptor (A) type molecules, PXZ-DBTO2 and PXZ-Ph-DBTO2, configured with phenoxazine donor and dibenzothiophene-S,S-dioxide acceptor are reported. PXZ-Ph-DBTO2, with a phenyl group introduced at the ortho position of PXZ, was used t... Read More about Effects of Ortho-Phenyl Substitution on the rISC Rate of D–A Type TADF Molecules.

Pyridylpyrazole N^N Ligands Combined with Sulfonyl-Functionalised Cyclometalating Ligands for Blue-Emitting Iridium(III) Complexes and Solution-Processable PhOLEDs (2017)
Journal Article
Benjamin, H., Fox, M. A., Batsanov, A. S., Al-Attar, H. A., Li, C., Ren, Z., …Bryce, M. R. (2017). Pyridylpyrazole N^N Ligands Combined with Sulfonyl-Functionalised Cyclometalating Ligands for Blue-Emitting Iridium(III) Complexes and Solution-Processable PhOLEDs. Dalton Transactions, 46, 10996-11007. https://doi.org/10.1039/c7dt02289a

A series of blue iridium(III) complexes (12–15) comprising sulfonyl-functionalised phenylpyridyl cyclometalating ligands and pyridylpyrazole N^N ligands are reported, with an X-ray crystal structure obtained for 12. The complexes are highly emissive... Read More about Pyridylpyrazole N^N Ligands Combined with Sulfonyl-Functionalised Cyclometalating Ligands for Blue-Emitting Iridium(III) Complexes and Solution-Processable PhOLEDs.

Photophysics of an Asymmetric Donor–Acceptor–Donor′ TADF Molecule and Reinterpretation of Aggregation-Induced TADF Emission in These Materials (2017)
Journal Article
Aydemir, M., Xu, S., Chen, C., Bryce, M. R., Chi, Z., & Monkman, A. P. (2017). Photophysics of an Asymmetric Donor–Acceptor–Donor′ TADF Molecule and Reinterpretation of Aggregation-Induced TADF Emission in These Materials. Journal of Physical Chemistry C, 121(33), 17764-17772. https://doi.org/10.1021/acs.jpcc.7b06299

We report an in-depth photophysical investigation of an asymmetric donor–acceptor–donor′ (D–A–D′) thermally activated delayed fluorescence (TADF) molecule (4-(9H-carbazol-9-yl)phenyl)(4-(10H-phenothiazin-10-yl)phenyl)sulfone and compare its photophys... Read More about Photophysics of an Asymmetric Donor–Acceptor–Donor′ TADF Molecule and Reinterpretation of Aggregation-Induced TADF Emission in These Materials.

An optical and electrical study of full thermally activated delayed fluorescent white organic light emitting diodes (2017)
Journal Article
Pereira, D., Santos, P., Ward, J., Data, P., Okazaki, Y., Minakata, S., …Monkman, A. (2017). An optical and electrical study of full thermally activated delayed fluorescent white organic light emitting diodes. Scientific Reports, 7(1), Article 6234. https://doi.org/10.1038/s41598-017-06568-3

We report on the engineering of full thermally activated delayed fluorescence – based white organic light emitting diodes (W-OLEDs) composed of three emitters (2,7-bis(9,9-dimethyl-acridin-10-yl)-9,9-dimethylthioxanthene-S,S-dioxide (DDMA-TXO2), 2,7-... Read More about An optical and electrical study of full thermally activated delayed fluorescent white organic light emitting diodes.

Optical and Polarity Control of Donor–Acceptor Conformation and Their Charge-Transfer States in Thermally Activated Delayed-Fluorescence Molecules (2017)
Journal Article
dos Santos, P. L., Ward, J. S., Batsanov, A. S., Bryce, M. R., & Monkman, A. P. (2017). Optical and Polarity Control of Donor–Acceptor Conformation and Their Charge-Transfer States in Thermally Activated Delayed-Fluorescence Molecules. Journal of Physical Chemistry C, 121(30), 16462-16469. https://doi.org/10.1021/acs.jpcc.7b03672

This study reports two novel D–A–D molecules, 2,7-bis(phenothiazin-10-yl)-9,9-dimethylthioxanthene-S,S-dioxide (DPT-TXO2) and 2,7-bis(1-methylphenothiazin-10-yl)-9,9-dimethylthioxanthene-S,S-dioxide (DMePT-TXO2), where the latter differs by only a me... Read More about Optical and Polarity Control of Donor–Acceptor Conformation and Their Charge-Transfer States in Thermally Activated Delayed-Fluorescence Molecules.

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.

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.

Photophysics of Thermally Activated Delayed Fluorescence Molecules (2017)
Journal Article
Dias, F. B., Penfold, T. J., & Monkman, A. P. (2017). Photophysics of Thermally Activated Delayed Fluorescence Molecules. Methods and Applications in Fluorescence, 5(1), Article 012001. https://doi.org/10.1088/2050-6120/aa537e

Thermally activated delayed fluorescence (TADF) has recently emerged as one of the most attractive methods for harvesting triplet states in metal-free organic materials for application in organic light emitting diodes (OLEDs). A large number of TADF... Read More about Photophysics of Thermally Activated Delayed Fluorescence Molecules.