Research Paper: Horizontally oriented MRCT-type TADF emitter achieving EQE over 40% for Sky-Blue OLED

Scientific Summary

This study introduces a novel design strategy for multi-resonance charge transfer (MRCT)-type thermally activated delayed fluorescence (TADF) emitters, DBACzPh and DBADCzPh, to achieve high-efficiency sky-blue organic light-emitting diodes (OLEDs). By extending the C-C bond, DBADCzPh achieved preferential 100% horizontal molecular orientation in a high-polarity PPF host matrix. This orientation, combined with balanced carrier transport and efficient host-to-dopant energy transfer, significantly boosts outcoupling efficiency. The DBADCzPh emitter in a PPF host achieved an exceptional external quantum efficiency (EQE) exceeding 40% (42.5%) for sky-blue electroluminescence at low voltages. The C-C bond also ensures higher molecular stability and accelerates reverse intersystem crossing (RISC) via 3LE states, leading to strong TADF emission and a high photoluminescence quantum yield (91%).

Why it Matters

These findings are crucial for developing next-generation blue OLEDs, offering a robust approach to overcome rapid degradation and limited efficiency often encountered in such emitters. This novel molecular design advances sustainable display and lighting technologies by providing a pathway to superior performance.

Publication Details

Barman, D., Tsuchiya, Y. & Adachi, C. (2025), Horizontally oriented MRCT-type TADF emitter achieving EQE over 40% for Sky-Blue OLED. Nature Communications, https://doi.org/10.1038/s41467-025-59893-x.

Fluxim Tools Used

The commercial software Setfos (Fluxim AG) was used for optical modeling and angular-dependent PL simulations to investigate and confirm the molecular orientation of emitters in doped films. Specifically, Setfos corroborated the critical finding of a close to 100% horizontal molecular orientation for DBADCzPh in the PPF host.