%0 Journal Article
%T Highly efficient blue thermally activated delayed fluorescence emitters based on symmetrical and rigid oxygen-bridged boron acceptors
%J -
%D 2019
%R https://doi.org/10.1038/s41566-019-0415-5
%X Materials that exhibit thermally activated delayed fluorescence are promising for the realization of efficient organic light-emitting diodes. However, finding suitable deep-blue thermally activated delayed fluorescence materials is still challenging. Here, we report two highly efficient deep-blue thermally activated delayed fluorescence emitters, TDBA每Ac and TDBA每DI, containing oxygen-bridged, symmetric and rigid boron acceptor moieties. Both emitters have been designed to have high photoluminescence quantum yield and narrow-band blue emission. TDBA每Ac and TDBA每DI exhibited deep-blue emission and a small singlet每triplet energy gap of 0.06ˋeV and 0.11ˋeV, respectively, in toluene. The 20wt%-doped films of TDBA每Ac and TDBA每DI in DBFPO host exhibited high photoluminescence quantum yields of 93% and 99%, respectively. The fabricated TDBA每DI device showed an extremely high external quantum efficiency of 38.15ˋ㊣ˋ0.42% in the blue region with low roll-off characteristics of 25.2% at high luminance of up to 5,000 cdˋm每2. The TDBA每Ac-doped device exhibited a high external quantum efficiency of 21.50ˋ㊣ˋ0.22% with deep-blue colour coordinates of (0.15, 0.06)
%U https://www.nature.com/articles/s41566-019-0415-5