The design of extended multiple resonance thermally activated delayed fluorescence emitter based on polycyclic amine/carbonyl system

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska Curie grant agreement No. 838009 (TSFP) and No. 838885 (NarrowbandSSL). D.S. acknowledges support from the Marie Skłodowska-Curie Individual Fellowship, the National Postdoctoral Program for Innovative Talents (BX201700164), the Jiangsu Planned Projects for Postdoctoral Research Funds (2018K011A). The St Andrews team would also like to thank the Leverhulme Trust (RPG-2016047) and EPSRC (EP/P010482/1) for financial support. We thank Umicore AG for the gift of materials. Computational resources have beenprovided by the Consortium des Équipements de Calcul In-tensif (CÉCI), funded by the Fonds de la Recherche Scientifiques de Belgique (F.R.S.-FNRS) under Grant No. 2.5020.11.The development of muliple resonance thermally activated delayed fluorescence (MR-TADF) materials possessing narrow emission spectra has attracted significant attention as emitters for high colour purity organic light emitting diodes (OLEDs). In this work, a simple design strategy is introduced to construct a MR-TADF emitter, DDiKTa, through dimerization of the known MR-TADF emitter DiKTa. This design permits concentration quenching to be largely suppressed, which is a known weakness of previously reported MR-TADF emitters. OLEDs based on DDiKTa show an EQEmax of 19% at a doping concentration of 9 wt%. The electrolumicence spectrum is red-shifted into the green, producing a rare example of a green-emitting MR-TADF OLED.Publisher PDFPeer reviewe