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Peripheral halogen atoms in multi-resonant thermally activated delayed fluorescence emitters : the role of heavy atom on intermolecular interactions and spin orbit coupling
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dc.contributor.author | Miranda-Salinas, Hector | |
dc.contributor.author | Wang, Jingxiang | |
dc.contributor.author | Danos, Andrew | |
dc.contributor.author | Matulaitis, Tomas | |
dc.contributor.author | Stavrou, Kleitos | |
dc.contributor.author | Monkman, Andrew P. | |
dc.contributor.author | Zysman-Colman, Eli | |
dc.date.accessioned | 2024-01-15T09:30:07Z | |
dc.date.available | 2024-01-15T09:30:07Z | |
dc.date.issued | 2024-02-14 | |
dc.identifier | 297559091 | |
dc.identifier | 4d1d5800-14a9-46e2-a959-bf7d32ca0695 | |
dc.identifier | 85183024121 | |
dc.identifier.citation | Miranda-Salinas , H , Wang , J , Danos , A , Matulaitis , T , Stavrou , K , Monkman , A P & Zysman-Colman , E 2024 , ' Peripheral halogen atoms in multi-resonant thermally activated delayed fluorescence emitters : the role of heavy atom on intermolecular interactions and spin orbit coupling ' , Journal of Materials Chemistry C , vol. 12 , no. 6 , pp. 1996-2006 . https://doi.org/10.1039/D3TC04394K | en |
dc.identifier.issn | 2050-7526 | |
dc.identifier.other | ORCID: /0000-0003-0470-7356/work/150659744 | |
dc.identifier.other | ORCID: /0000-0001-7183-6022/work/150661468 | |
dc.identifier.uri | https://hdl.handle.net/10023/29009 | |
dc.description | This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska Curie grant agreement Nos 812872 and 101073045 (TADFlife and TADFsolutions). J.W. thanks the China Scholarship Council (202006250026). | en |
dc.description.abstract | Multi-resonant thermally activated delayed fluorescence materials (MR-TADF) can show narrow-band emission with high photoluminescence quantum efficiency, desirable for applications in organic light emitting diodes (OLEDS). However, they frequently suffer from slow reverse intersystem crossing (RISC) compared to established donor-acceptor TADF emitters, leading to severe device efficiency roll-off at high exciton densities. Introducing heavy atom effects (HAE) by core-substitution has been previously shown to enhance spin orbit coupling and thus RISC in MR-TADF emitters, frequently with oxygen atoms replaced by isoelectronic sulfur or selenium. Here, we explore an alternate HAE strategy using peripheral halogenation of the MR-TADF DiKTa core, comparing tBr-DiKTa and dBr-tBu-DiKTa with non-halogenated Mes3-DiKTa. The two brominated emitters demonstrate improved kRISC because of the HAE, while the rate appears to improve by an additional order of magnitude in mCP host, because of intermolecular (guest-host) interaction. Despite the beneficial hetero-intermolecular interactions, strong homo-intermolecular interactions result in enhanced non-radiative pathways and lower photoluminescence quantum yields. OLEDs of dBr-tBu-DiKTa hence showed comparable EQEmax with Mes3-DiKTa (21%) and improved efficiency roll-off until 500 cd m-2, although with accelerated roll-off beyond a critical current density. Together with comparisons in less strongly doped devices, these results show that the HAE provided by peripheral halogens improves the device performance up to 500 cd m-2, but also support detrimental intermolecular interactions that dominate at higher device currents. | |
dc.format.extent | 11 | |
dc.format.extent | 2620343 | |
dc.language.iso | eng | |
dc.relation.ispartof | Journal of Materials Chemistry C | en |
dc.subject | QD Chemistry | en |
dc.subject | DAS | en |
dc.subject.lcc | QD | en |
dc.title | Peripheral halogen atoms in multi-resonant thermally activated delayed fluorescence emitters : the role of heavy atom on intermolecular interactions and spin orbit coupling | en |
dc.type | Journal article | en |
dc.contributor.sponsor | European Commission | en |
dc.contributor.institution | University of St Andrews. School of Chemistry | en |
dc.contributor.institution | University of St Andrews. Institute of Behavioural and Neural Sciences | en |
dc.contributor.institution | University of St Andrews. Centre for Energy Ethics | en |
dc.contributor.institution | University of St Andrews. Organic Semiconductor Centre | en |
dc.contributor.institution | University of St Andrews. EaSTCHEM | en |
dc.identifier.doi | 10.1039/D3TC04394K | |
dc.description.status | Peer reviewed | en |
dc.identifier.grantnumber | 812872 | en |
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