A Boron, Nitrogen, and Oxygen Doped π‐Extended Helical Pure Blue Multiresonant Thermally Activated Delayed Fluorescent Emitter for Organic Light Emitting Diodes That Shows Fast k RISC Without the Use of Heavy Atoms

Abstract Narrowband emissive multiresonant thermally activated delayed fluorescence (MR‐TADF) emitters are a promising solution to achieve the current industry‐targeted color standard, Rec. BT.2020‐2, for blue color without using optical filters, aiming for high‐efficiency organic light‐emitting diodes (OLEDs). However, their long triplet lifetimes, largely affected by their slow reverse intersystem crossing rates, adversely affect device stability. In this study, a helical MR‐TADF emitter ( f ‐DOABNA) is designed and synthesized. Owing to its π‐delocalized structure, f ‐DOABNA possesses a small singlet‐triplet gap, Δ E ST , and displays simultaneously an exceptionally faster reverse intersystem crossing rate…

• CU
  City University of Hong Kong

  Awards: 9231531, 9610637
• GW
  Gouvernement Wallon

  Award: n1117545
• JS
  Japan Society for the Promotion of Science London

  Award: JPJSCCA20180005
• EC
  European Commission

  Award: 838885
• FD
  Fonds De La Recherche Scientifique - FNRS

  Awards: 2.5020.11, 2.5020
• FW
  Fédération Wallonie-Bruxelles

  Awards: 2.5020.11, n1117545
• H2
  Horizon 2020 Framework Programme

  Award: 838885
• EA
  Engineering and Physical Sciences Research Council

  Awards: EP/W007517/1, EP/R035164/1, EP/R035164/1, EP/R035164, EP/W007517/1, EP/W007517
• JS
  Japan Society for the Promotion of Science

  Award: JPJSCCA20180005