Researchers develop high-performance blue organic LEDs based on thermally activated delayed fluorescence material

Organic light-emitting diodes (OLEDs) have become a leading display technology. The luminescent material is a core component of OLEDs. Thermally activated delayed fluorescence (TADF) materials have emerged as promising emitters for achieving high-efficiency OLEDs.

Blue TADF-OLEDs confront more pronounced efficiency roll-off and material degradation issues compared to their green and red counterparts, owing to the formation of high-energy excitons through bimolecular reactions of long-lived excited states.

To pave the way for future TADF-OLED applications, it is crucial to develop advanced blue TADF molecules with extremely short exciton lifetimes, ideally in the nanosecond scale. Simultaneously achieving a high photoluminescence quantum yield (PLQY), ultrashort exciton lifetime, and suppressed concentration quenching in TADF materials is desirable yet challenging.

In a study published in Advanced Materials, a research group led by Prof. Lu Canzhong from Fujian Institute of Research on the Structure of Matter of the Chinese Academy of Sciences reported a new strategy for designing high-performance blue TADF materials, and developed a blue TADF material with high emission efficiency, nanosecond emission lifetime, and effectively suppressed concentration quenching, enabling the realization of high-performance nondoped and doped blue OLEDs.

The researchers designed and synthesized a acceptor-donor-acceptor (A-D-A) type TADF molecule, namely 2BO-sQA, bearing a dispirofluorene-quinolinoacridine (sQA) donor and two cofacial oxygen-bridged triarylboron (BO) acceptors which are nearly orthogonal to the sQA donor.