Seminário com Prof. Dr. Andrew Monkman – 25 de agosto de 2023 (sexta-feira) – 10h15min
O PROGRAMA DE PÓS-GRADUAÇÃO EM FÍSICA convida para o seminário:
Turning green light into blue and poor TADF molecules into something special
Prof. Andrew Paul Monkman
Physics Department, University of Durham – UK
*Evento de presença obrigatória da disciplina seminários
Abstract:
DMAC TRZ is a very typical green thermally activated delayed fluorescence emitter. Assumed to be very well characterized in the literature, giving OLEDs with EQE well above 25% through enhanced out-coupling as the molecule self-orients when deposited by vacuum deposition. Thus, a good OLED emitter nothing exceptional so let’s move on to something else. Well, hang on a minute, that’s not all, in fact as we will show in this talk, this is far from the end of the story, if you are prepared to look. And we did! We noticed that when we used DMAC TRZ as a sensitizer for v-DABNA, a so called MR-TADF narrow line width emitter, we managed to generate pure blue light, i.e. we turned green DMAC TRZ emission into pure blue emission. After a bit of head scratching we concluded that either the FRET sensitization was immaculate or something new was going on with DMAC TRZ. After looking hard we found something rather strange, a second high energy emitting state in DMAC TRZ, which is a weak charge transfer state, and looks very much like an axial conformer, i.e. the donor is folded out of the plane of the acceptor compared to the more usually rotated through 90o twisted equatorial conformer that gives rise to the strong green CT state. We have reported on such axial and equatorial conformers before in DPTZ-DBTO2 but these state come about because of the buckled configuration of the phenothiazine donor units. Whereas in DMAC TRZ the acridine units are planar. So, what causes these conformers in DMAC TRZ, what new photophysics do they give and are they involved in the sensitization step to v-DABNA to give efficient pure blue emission. We will try to explain all in the talk!
Data: 25 de agosto de 2023 (sexta-feira) – Horário: 10h15min
Local: Sala 212 – Auditório do Departamento de Física
Agenda de Seminários: https://ppgfsc.posgrad.ufsc.br/seminarios/
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