π-Stacked Donor-Acceptor Dendrimers for Highly Efficient White Electroluminescence

pi-Stacked dendrimers consisting of cofacially aligned donors and acceptors are developed by introducing three dendritic teracridan donors with orthogonal configuration and three triazine acceptors in periphery of hexaphenylbenzene skeleton. The dendritic structure and orthogonal configuration of teracridan not only make their outer acridan segments approaching to acceptor in close distance, but also fix donor and acceptor in face-to-face alignment, leading to through-space charge transfer emission with thermally activated delayed fluorescence (TADF) effect. By regulating charge transfer strength via substituent effect of acceptor, emission color of the dendrimers can be tuned from blue to yellow/red region. Solution-processed two-color white organic light-emitting diodes (OLEDs) based on blue and yellow pi-stacked donor-acceptor dendrimers exhibit the maximum external quantum efficiency of 20.6 % and maximum power efficiency of 58.9 lm W-1, representing the state-of-the-art efficiency for all-TADF white OLEDs by solution process.

Automated summary

Pi-stacked dendrimers with cofacial alignment of donors and acceptors were developed by introducing unique dendritic teracridan donors and triazine acceptors, leading to through-space charge transfer emission with thermally activated delayed fluorescence. By adjusting the charge transfer strength, the emission color of the dendrimers can be tuned, achieving high efficiency two-color white OLEDs.