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 study, a novel surface-functionalized carbon dot was designed and prepared by co-modification with urea and (3-aminopropyl) triethoxysilane (APTES), effectively overcoming the bottleneck of low photoluminescence quantum yields (PL QYs) of traditional color-changing afterglow materials. The obtained material exhibited wavelength-tunable long-lasting phosphorescence emission ranging from orange to green, with a PL QY as high as 70.40%. Experimental results demonstrate that the incorporation of urea and APTES not only promotes efficient intersystem crossing (ISC) but also establish a multi-confinement microenvironment, thereby effectively suppressing nonradiative decay of triplet excitons. The material's practical utility is further demonstrated in advanced information anti-counterfeiting and afterglow display applications, highlighting its promising technological potential.