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The solubility of luminescent materials is a key parameter to improve the electroluminescent performances of solution-processed organic light-emitting diodes (OLEDs). The through-space charge transfer (TSCT) materials provide an alternative to introduce the solubilizing groups (SGs) to the linker. Herein, the tert-butyl and n-hexyl groups are introduced as SGs at C7 positions of spiro structure, named C6-DMB and tBu-DMB, away from the acceptor. This has no influence on the photophysical properties of the parent TSCT molecule. Highly efficient solution-processed OLEDs were demonstrated with the maximum external quantum efficiencies of 21.0% and 21.7%, respectively. To the best of our knowledge, these are champions in the state-of-the-art solution-processed OLEDs with TSCT emitters. This work confirmed our conjecture of constructing highly efficient soluble emitters by transforming an outstanding TSCT material from thermal evaporation to solution-processed OLEDs with SGs simply integrated on the 'bridge' linker. [ABSTRACT FROM AUTHOR]

Multi‐layer π‐stacked emitters based on spatially confined donor/acceptor/donor (D/A/D) patterns have been developed to achieve high‐efficiency thermally activated delayed fluorescence (TADF). In this case, dual donor moieties and a single acceptor moiety are introduced to form two three‐dimensional (3D) emitters, DM‐BD1 and DM‐BD2, which rely on spatial charge transfer (CT). Owing to the enforced face‐to‐face D/A/D pattern, effective CT interactions are realized, which lead to high photoluminescence quantum yields (PLQYs) of 94.2 % and 92.8 % for the two molecules, respectively. The resulting emitters exhibit small singlet–triplet energy splitting (ΔEST) and fast reverse intersystem crossing (RISC) processes. Maximum external quantum efficiencies (EQEs) of 28.0 % and 26.6 % were realized for devices based on DM‐BD1 and DM‐BD2, respectively, which are higher than those of their D/A‐type analogues. [ABSTRACT FROM AUTHOR]