陈先凯教授及其合作者在Angew. Chem. Int. Ed.上发表论文

作者：

Rajat Walia^1#, Xiaochun Fan^1#, Le Mei³, Weixiong Guo³, Kai Wang^1,4, Chihaya Adachi²,* Xian-Kai Chen^1,2,5,* and Xiao-Hong Zhang^1,5

单位：

¹Institute of Functional Nano and Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, Jiangsu,P.R. China.

²Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 15 Fukuoka 819-0395, Japan.

³Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, P.R. China

⁴Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu, P.R. China.

⁵Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, Jiangsu, P.R. China.

摘要：

Both reducing singlet-triplet energy gaps (ΔE_S1T1) and enhancing spin-orbit couplings (SOCs) are key to improving reverse intersystem crossing rates (k_RISC) in thermally activated delayed fluorescence (TADF) materials. While considerable efforts have focused on reducing ΔE_S1T1, investigations on SOCs remain limited. Here, blocking π-conjugation in carbonyl-embedded polycyclic heteroaromatic (PHA) molecules as potential approach to elevate ππ* excitation energy, allowing its hybridization with nπ* excitation, thereby increasing SOCs is proposed. Two proof-of-concept isomers, DNDK-1 and DNDK-2 are synthesized, with different orientations of carbonyl units. DNDK-1 adopts a heavily twisted structure that hinders π-conjugation, while DNDK-2 remains quasi-planar, maintaining stronger π-conjugation. Experimental measurements reveals stark differences in their photophysical properties, with DNDK-1 exhibiting faster k_RISC and much higher electroluminescence efficiency. The ab-initio calculations elucidate that hindered conjugation in DNDK-1 elevates ππ* excitation energy, enabling nπ*-ππ* mixing, thus significantly boosting SOCs. In contrast, smooth π-conjugation in DNDK-2 leads to marginal nπ*-ππ* mixing. In addition, utilizing groups composed of meta-arranged carbonyl-Ar-carbonyl and meta-arranged N-Ar-N units emerges as another approach to block π-conjugation and enhance SOCs. This joint experimental and theoretical work provides promising pathways to enhance SOCs by blocking π-conjugation, offering crucial insights for designing carbonyl-embedded PHA emitters with larger SOCs.

影响因子：

16.1

分区情况：

一区

链接：

https://onlinelibrary.wiley.com/doi/10.1002/anie.202503371