Serevičius Tomas, Tumkevičius Sigitas, Dodonova-Vaitku Nienė Jelena, Juršėnas Saulius
Vilnius University, Faculty of Physics, Institute of Photonics and Nanotechnology, Sauletekio 3, LT-10257 Vilnius, Lithuania.
Vilnius University, Faculty of Chemistry, Institute of Chemistry, Naugarduko 24, LT-03225 Vilnius, Lithuania.
J Phys Chem Lett. 2025 Mar 27;16(12):3100-3105. doi: 10.1021/acs.jpclett.5c00241. Epub 2025 Mar 18.
Donor-acceptor-based thermally activated delayed fluorescence (TADF) emitters have a complicated energy level scheme with multiple singlet and triplet energy levels. Among them, TADF compounds with the lowest-energy charge-transfer triplet state (type III compounds) are especially interesting due to their specific emission properties. We show that type III TADF compounds may show dual phosphorescence at low temperatures as well as weak high-energy emission at room temperature, somewhat resembling the phosphorescence spectrum of the local triplet. Such untypical behavior was demonstrated only in compounds with a low energy gap between the triplet states of different character, imposing efficient communication between them through vibronic coupling.
基于供体-受体的热激活延迟荧光（TADF）发光体具有复杂的能级结构，包含多个单重态和三重态能级。其中，具有最低能量电荷转移三重态的TADF化合物（III型化合物）因其特殊的发射特性而格外引人关注。我们发现，III型TADF化合物在低温下可能会表现出双重磷光，在室温下则会有较弱的高能发射，这在一定程度上类似于局域三重态的磷光光谱。这种非典型行为仅在不同性质三重态之间能隙较小的化合物中得到证实，这使得它们通过振动耦合实现了有效的相互作用。
