Small-molecule based thermally activated delayed fluorescence materials with dual-emission characteristics

Organic thermally activated delayed fluorescence(TADF) emitters have attracted increasing concerns, owing to their atypical photophysical features that can pave the way to the innovative engineering applications. As cutting-edge type of luminescent molecules, however, most of them only exert a single-wavelength emission from the lowest excited state, according to Kasha's rule. To develop their potential applications in multicolor luminescence and multi-functional luminescent probes for biological imaging, researchers have begun to turn their attention to design organic TADF molecules with dual-emission characteristics, by employing an additional fluorescence, phosphorescence, or TADF signal within a single-component system. We herein summarized the design principles as well as the luminescence mechanism of organic donor-acceptor TADF compounds with dual-emission characteristics, the superiority of which can cover unique material applications in modern luminescencerelated fields.