Charge Transfer Excited State Promoted Multiple Resonance Delayed Fluorescence Emitter for High-Performance Narrowband Electroluminescence

Multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters are promising candidates for narrowband organic light-emitting diodes, but their electroluminescent performance is typically hindered by the slow reverse intersystem crossing rate (kRISC). Herein, we present an effective strategy to introduce a multichannel reverse intersystem crossing (RISC) pathway with large spin–orbit coupling by orthogonally linking an electron-donating unit to the MR framework. Through delicate manipulation of the excited-state energy levels, an additional intersegmental charge transfer triplet state could be “silently” induced without perturbing the MR character of the lowest excited singlet state. The…

• NN
  National Natural Science Foundation of China

  Award: 52130308
• ST
  Science, Technology and Innovation Commission of Shenzhen Municipality

  Awards: ZDSYS20210623091813040, 20200810150858002, JCYJ20220531101215034
• BA
  Basic and Applied Basic Research Foundation of Guangdong Province

  Award: 2023A1515030005