Journal
FRONTIERS IN CHEMISTRY
Volume 8, Issue -, Pages -Publisher
FRONTIERS MEDIA SA
DOI: 10.3389/fchem.2020.00750
Keywords
OLEDs; TADF; emitter orientation; molecular orientation; emitter-host interaction
Categories
Funding
- EU Horizon 2020 MSC ITN TADFlife [812872]
- Deutsche Forschungsgemeinschaft (DFG) [Br 1728/20-1]
- Chinese Scholarship Council (CSC) [201606890009]
Ask authors/readers for more resources
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 T(g)and its tendency for alignment being expressed, e.g., as birefringence or the formation of a giant surface potential of the host. Electrostatic dipole-dipole interactions between host and emitter are not found to play an important role.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available