Aggregation‐Induced Delayed Fluorescence Luminogens for Efficient Organic Light‐Emitting Diodes.

Aggregation‐induced delayed fluorescence (AIDF) can be regarded as a special case of aggregation‐induced emission (AIE). Luminogens with AIDF can simultaneously emit strongly in solid state and fully utilize the singlet and triplet excitons in organic light‐emitting diodes (OLEDs). In this work, two new AIDF luminogens, DMF‐BP‐DMAC and DPF‐BP‐DMAC, with an asymmetric D–A–D′ structure, are designed and synthesized. The characteristics of both luminogens are systematically investigated, including single crystal structures, theoretical calculations, photophysical properties and thermal stabilities. Inspired by their AIDF nature, the green‐emission non‐doped OLEDs based on them are fabricated, which afford good electroluminescence performances, with low turn‐on voltages of 2.8 V, high luminance of 52560 cd m−2, high efficiencies of up to 14.4 %, 42.3 cd A−1 and 30.2 lm W−1, and very small efficiency roll‐off. The results strongly indicate the bright future of non‐doped OLEDs on the basis of robust AIDF luminogens. Brighter than the Sun: Aggregation‐induced delayed fluorescence luminogens are designed and synthesized, and non‐doped OLEDs based on them afford high external quantum efficiencies of up to 14.4 % with very small efficiency roll‐offs. [ABSTRACT FROM AUTHOR]