| Autor: |
Chapran M; Department of Molecular Physics , Lodz University of Technology , Zeromskiego 116 , 90-924 Lodz , Poland., Pander P; Physics Department , Durham University , South Road, Durham DH1 3LE , United Kingdom., Vasylieva M; Faculty of Chemistry , Silesian University of Technology , M. Strzody 9 , 44-100 Gliwice , Poland., Wiosna-Salyga G; Department of Molecular Physics , Lodz University of Technology , Zeromskiego 116 , 90-924 Lodz , Poland., Ulanski J; Department of Molecular Physics , Lodz University of Technology , Zeromskiego 116 , 90-924 Lodz , Poland., Dias FB; Physics Department , Durham University , South Road, Durham DH1 3LE , United Kingdom., Data P; Physics Department , Durham University , South Road, Durham DH1 3LE , United Kingdom.; Faculty of Chemistry , Silesian University of Technology , M. Strzody 9 , 44-100 Gliwice , Poland.; Centre of Polymer and Carbon Materials , Polish Academy of Science , M. Curie-Sklodowskiej 34 , 41-819 Zabrze , Poland. |
| Abstrakt: |
The investigation of nondoped exciplex blends of 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine (PO-T2T), working as the one-electron acceptor molecule, with different electron donors is reported. The emissions of these exciplexes span from the blue to orange-red regions, showing clear contribution from thermally activated delayed fluorescence (TADF) and delayed fluorescence originated from nongeminate recombination of charge carriers created by the dissociation of optically generated exciplexes. We focus our studies on the properties of TADF in these systems, covering in particular the physical meaning of the different transient components observed in their luminescence decays. Our results unravel the intricate role of reverse intersystem crossing due to spin-orbit coupling and possibly also due to hyperfine interactions and internal conversion, which affect the efficiency of the TADF mechanism. Remarkable performances are obtained in prototype organic light-emitting diodes fabricated with some of these blends. Green exciplex blends, in particular, exhibited the current efficiency of 60 cd A -1 , power efficiency of 71 lm W -1 , and external quantum efficiency of 20%. We believe that our results will contribute significantly to highlight the potential advantages of intermolecular exciplexes in the area of organic light-emitting diodes. |
