Efficient Carbon Dot-Based Phosphorescent Materials with Time-Dependent Color-Changing through Surface Modification

Abstract

Time-dependent color-changing afterglow materials enable enhanced encryption capabilities through temporal spectral evolution, attracting significant research interest in recent years. Although substantial progress has been achieved in modulating dynamic emission colors, the relatively low luminescence efficiency of these materials remains a key challenge. In this work, carbon dots (CDs) were surface-modified with urea and (3-aminopropyl) triethoxysilane (APTES), yielding a color-changing afterglow material exhibiting a high photoluminescence quantum yield of 70.40% and a time-resolved emission shift from orange to green. Experimental results demonstrate that the incorporation of urea and APTES not only promotes efficient intersystem crossing but also effectively suppresses non-radiative decay pathways, thereby enhancing radiative output. The material's practical utility is further demonstrated in advanced information anti-counterfeiting and afterglow display applications, highlighting its promising technological potential.