Angew. Chem. Int. Ed.: Introducing Spiro-locks into the Nitrogen/Carbonyl System towards Efficient Narrowband Deep-blue Multi-resonance TADF Emitters

Title：

Introducing Spiro-locks into the Nitrogen/Carbonyl System towards Efficient Narrowband Deep-blue Multi-resonance TADF Emitters

Authors：

You-Jun Yu^1# , Zi-Qi Feng^1# , Xin-Yue Meng¹, Long Chen¹, Fu-Ming Liu¹, Sheng-Yi Yang¹, Dong-Ying Zhou¹, Liang-Sheng Liao^1,2, and Zuo-Quan Jiang¹*

Institutions：

¹Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China.

²Macau Institute of Materials Science and Engineering, Macau University of Science and Technology, Macao, 999078, China.

Abstract：

The current availability of multi-resonance thermally activated delayed fluorescence (MR-TADF) materials with excellent color purity and high device efficiency in the deep-blue region is appealing. To address this issue in the emerged nitrogen/carbonyl MR-TADF system, we propose a spiro-lock strategy. By incorporating spiro functionalization into a concise molecular skeleton, a series of emitters (SFQ, SOQ, SSQ, and SSeQ) can enhance molecular rigidity, blue-shift the emission peak, narrow the emission band, increase the photoluminescence quantum yield by over 92 %, and suppress intermolecular interactions in the film state. The referent CZQ without spiro structure has a more planar skeleton, and its bluer emission in the solution state redshifts over 40 nm with serious spectrum broadening and a low PLQY in the film state. As a result, SSQ achieves an external quantum efficiency of 25.5 % with a peak at 456 nm and a small full width at half maximum of 31 nm in a simple unsensitized device, significantly outperforming CZQ. This work discloses the importance of spiro-junction in modulating deep-blue MR-TADF emitters.

IF：

16.823

Link：

https://onlinelibrary.wiley.com/doi/10.1002/anie.202310047