Long-lived spin-polarized intermolecular exciplex states in thermally activated delayed fluorescence-based organic light-emitting diodes.

ABSTRACT: Spin-spin interactions in organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) are pivotal because radiative recombination is largely determined by triplet-to-singlet conversion, also called reverse intersystem crossing (RISC). To explore the underlying process, we apply a spin-resonance spectral hole-burning technique to probe electroluminescence. We find that the triplet exciplex states in OLEDs are highly spin-polarized and show that these states can be decoupled from the heterogeneous nuclear environment as a source of spin dephasing and can even be coherently manipulated on a spin-spin relaxation time scale T₂* of 30 ns. Crucially, we obtain the characteristic triplet exciplex spin-lattice relaxation time T₁

SUBMITTER: Weissenseel S 

PROVIDER: S-EPMC8598001 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature