Developing single silane-derived delayed fluorescent carbon dots as donors for energy transfer-based aqueous-phase multicolor afterglow application

Developing aqueous-phase and metal-free room temperature (RT) long-afterglow materials should be of great significance for printable anti-counterfeiting encryption, LEDs and autofluorescence-free biosensing and bioimaging. However, the utility and reliability are greatly limited by the unstable structure of organic phosphors and thermally and moisture-induced emission quenching. Herein, silane-derived aqueous-phase delayed fluorescence (DF) carbon dots (CDs) were prepared using a hydrothermal route with 1,3-bis (3-aminopropyl)-1, 1,3,3-tetramethyldisiloxane as a single carbon precursor. The formed Si, N self-doped CDs subsequently embedded in a silica matrix (denoted as DF-CDs@SiO2) display bright blue RT-DF with a fluorescence quantum yield (QY) of 35.11% and an afterglow lifetime of about 434 ms, which can be observed with the naked eye for 10 s. The silica network formed by the hydrolysis of the silica-oxygen bonds in the silane can effectively limit the vibrations of the underlying chromophore of the CDs and achieve efficient DF emission. In particular, DF-CDs@SiO2 can be used as an efficient donor for multicolor afterglow via Forster resonance energy transfer, which has strong potential for applications in advanced information encryption, LEDs, hydrogel-based biosensing, and autofluorescence-free bioimaging.