Colorful, time-dependent carbon dot-based afterglow with ultralong lifetime

Metal-free afterglow materials have brought about widespread attention due to application advantages. Nevertheless, it is an attractive but formidable challenge to achieve long-persistent afterglow materials with high quantum yield (QY) at ambient conditions. Particularly, those with tunable afterglow are very rare. Herein, an economical strategy is proposed to construct a series of multi-color (cyan, green and orange) afterglow materials via one-step melting (within 5-10 min) of boric acid (BA) with unconventional precursors. The highly rigid framework, B C bond and hydrogen bond interactions can efficiently inhibit non-radiative deactivation by locking the triplet excitons in carbon dots (CDs) clusters. 66.13% high QY and 1.74 s long lifetime have been achieved simultaneously, as well as the afterglow can be observed by naked eyes for ~ 26 s. According to the adjustment of the precursor structure, dynamic afterglow color-changing (from orange, yellow, white to cyan) material was successfully realized. These excellent features allow them to be more applicable in time-resolved information security. In brief, this work provides a simple, flexible and effective strategy to construct highly efficient afterglow materials, and further facilitates their optical regulation and various potential applications.

Automated summary

This study proposes an economical method to construct multi-color afterglow materials with high quantum yield and long lifetime. By adjusting the precursor structure, dynamic color-changing afterglow was achieved, showing great potential for applications.