Template-Modulated Afterglow of Carbon Dots in Zeolites: Room-Temperature Phosphorescence and Thermally Activated Delayed Fluorescence

Room-temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) materials with long afterglow lifetimes have aroused considerable interest. Here, we successfully achieve the modulation of RTP and TADF properties in a carbon dots (CDs)-in-zeolite system based on different organic templates via an in situ solvothermal synthetic method. Benefitting from the efficient stabilizing effect of triplet states of CDs by SBT zeolite matrix, CDs@SBT-1 with a larger singlet–triplet energy gap (ΔEST) of 0.36 eV exhibits predominant RTP with a lifetime of 574 ms, while CDs@SBT-2 with a smaller ΔEST value of 0.18 eV shows TADF with a lifetime of 153 ms. Further investigations reveal that different organic templates result in different CDs structures, thus modulating the ΔEST values of CDs@zeolites. This work demonstrates a facile strategy to modulate the afterglow properties of CDs@zeolite composites, which opens the possibility of designing the novel afterglow materials desired for various advanced applications.