Designing dual emitting cores for highly efficient thermally activated delayed fluorescent emitters

Abstract

Designing dual emitting cores for constructing TADF materials with small ΔESTs, intensive absorption and high PLQYs.

Structural Design of Blue‐to‐Red Thermally‐Activated Delayed Fluorescence Molecules by Adjusting the Strength between Donor and Acceptor

“…In 2018, Yang et al synthesized two highly efficient green TADF emitters (2,2'-DPXZ-PN and 3,3'-DPXZ-PN) based on the dual emitting core strategy (Figure 14). [66] Compared with the PL emission of single chromophore PXZ-PN (491 nm) in doped CBP films, 2,2'-DPXZ-PN and 3,3'-DPXZ-PN exhibited redshifted emission peaked at 532 nm and 523 nm with the PLQYs of 67% and 82% evaluated under oxygen free conditions. On account of the increased conjugation degree and the efficient HOMO-LUMO separation, the dual chromophores exhibited bathochromic shifted emission and higher PLQY via the increased excitation and emission channels.…”

Fused tetracyclic tris[1,2,4]triazolo[1,3,5]triazine as a novel rigid electron acceptor for efficient thermally activated delayed fluorescence emitters

“…The intermediates 4-(10H-phenoxazin-10-yl)benzonitrile (PXZ-BN) and 4-(9,9-dimethylacridin-10(9H)-yl)benzonitrile (DMAC-BN) were synthesized according to reported literature. 43,44 Cyanuric chloride, PXZ and DMAC were purchased from commercial sources and used as received.…”

Thermally Activated Delayed Fluorescence Materials: Towards Realization of High Efficiency through Strategic Small Molecular Design

“…Yang et al. also reported two dual‐core‐design based TADF materials with a much more reduced Δ E ST and stronger absorption coefficient . The RISC process, radiative efficiency, and quantum yield are all simultaneously enhanced to a large extent, resulting in decent device performances.…”

“…Yang et al also reportedt wo dual-coredesign based TADF materials with am uch more reduced DE ST and stronger absorption coefficient. [57] The RISC process, radiative efficiency,a nd quantum yield are all simultaneously enhanced to alarge extent, resulting in decent device performances. The corresponding devices with dual-core emitters 5,50di(10H-phenoxazin-10-yl)-[1,10-biphenyl]-2,20-dicarbonitrile (2,2'-DPX-PN) and 6,60-di(10H-phenoxazin-10-yl)-[1,10-biphenyl]-3,30-dicarbonitrile (3,3'-DPX-PN) exhibit maximum EQE of 13.4 and 14.9 %a nd very slow efficiency roll-off of 12 and 13.5 %a tt he luminance of 1000 cd m À2 ,r espectively.L ee et al later reportedasimilar concept by connecting two TADF emitters with interlocked molecular design to create ar educed FWHM of only 48 nm through restricted molecular motion, and achieved high EQE of 14.0 %i nt he deep-blue region.…”