标题/Title：
影响因子/Impact Factor：13.3
链接/Link：https://www.sciencedirect.com/science/article/abs/pii/S1385894724080203?via%3Dihub
摘要/Abstract：
Single organic molecular materials exhibiting dual photoluminescence across the entire visible region hold considerable significance in lighting and display applications. Nevertheless, the molecular design and its applicability to dual electroluminescence organic light-emitting diodes (OLEDs) remain challenging. Herein, we systematically introduced carbazole-based weak donor (DW) units into the common phenothiazine (PT)-based strong donor (DS)-acceptor (A) fragments, yielding four DS-A-DW type thermally activated delayed fluorescence (TADF) materials: p-CZTRPT, p-OMeCZTRPT, o-CZTRPT, and o-OMeCZTRPT. The substitutional and isomeric engineering strategy of the DW units significantly modulates the dual photo/electroluminescence characteristics. The short wavelength (SW) emission band (∼400–500 nm) of these materials is found to originate from the mixed π → π* transitions localized on PT-phenyl units and DW units under low concentration conditions rather than quasi axial conformer of PT (QAPT). Incorporating 0.7/1 wt% of p-CZTRPT and p-OMeCZTRPT as emissive layers in solution-processed OLED devices exhibited dual electroluminescence (EL) with a maximum EQE of 7.60%/17.35% and 11.59%/19.74%, respectively, representing among the highest reported values for the single molecular PT based dual electroluminescent materials. This work underscores the limited role of QAPT in governing SW emission and demonstrates the effectiveness of substituent and isomer engineering of the DW units in modulating the dual photo/electroluminescence not only at the molecular level but also in light-emitting devices.
