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What Controls the Orientation of TADF Emitters?

Naqvi, Bilal A.; Schmid, Markus; Crovini, Ettore; Sahay, Prakhar; Naujoks, Tassilo; Rodella, Francesco; Zhang, Zhen; Strohriegl, Peter; Bräse, Stefan; Zysman-Colman, Eli; Brütting, Wolfgang

Abstract:
Thermally-activated delayed fluorescence (TADF) emitters—just like phosphorescent ones—can in principle allow for 100% internal quantum efficiency of organic light-emitting diodes (OLEDs), because the initially formed electron-hole pairs in the non-emissive triplet state can be efficiently converted into emissive singlets by reverse intersystem crossing. However, as compared to phosphorescent emitter complexes with their bulky—often close to spherical—molecular structures, TADF emitters offer the advantage to align them such that their optical transition dipole moments (TDMs) lie preferentially in the film plane. In this report, we address the question which factors control the orientation of TADF emitters. Specifically, we discuss how guest-host interactions may be used to influence this parameter and propose an interplay of different factors being responsible. We infer that emitter orientation is mainly governed by the molecular shape of the TADF molecule itself and by the physical properties of the host—foremost, its glass transition temperature Tg and its tendency for alignment being expressed, e.g., as birefringence or the formation of a giant surface potential of the host. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000125536
Veröffentlicht am 30.10.2020
Originalveröffentlichung
DOI: 10.3389/fchem.2020.00750
Scopus
Zitationen: 1
Web of Science
Zitationen: 1
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Organische Chemie (IOC)
Institut für Biologische und Chemische Systeme (IBCS)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 2296-2646
KITopen-ID: 1000125536
HGF-Programm 47.01.01 (POF III, LK 01)
Biol.Netzwerke u.Synth.Regulat. ITG+ITC
Erschienen in Frontiers in Chemistry
Band 8
Seiten Art. Nr.: 750
Vorab online veröffentlicht am 04.09.2020
Schlagwörter OLEDs, TADF, emitter orientation, molecular orientation, emitter-host interaction
Nachgewiesen in Scopus
Web of Science
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