Triple Matrix Confinement‐Induced Ultrabright Afterglow From Carbon Dots With Multivariate Responsive Afterglow Colors for Advanced Dynamic Information Encryption

ABSTRACT Dynamic afterglow carbon dots (CDs) materials, capable of long‐duration emission and dynamic color changes after excitation, hold promise for widespread applications in high‐level encryption and visual sensing. However, the single‐variable response afterglow color changing limits the potential of CDs for multidimensional information encoding and dynamic encryption in complex environments. Here, we report metal‐free CDs with triple‐variable responses (time, temperature, and excitation wavelength) for multiple dynamic afterglow colors and an ultra‐high afterglow brightness (406 cd m −2 ) far exceeding those of other afterglow materials. Based on the synergistic effect of triple matrix confinement and interface effects, room‑temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) are integrated into a single CD system. Owing to the different lifetimes of the dual‐mode afterglow (phosphorescence and TADF) and their varying sensitivities to temperature and excitation wavelength, time‐dependent afterglow colors (TDAC), excitation‐dependent afterglow colors (EDAC), and thermochromic afterglow (TCAG) are simultaneously achieved. Finally, we also designed a three‐dimensional variable‐response color code that varies with time, temperature, and excitation wavelength, spanning the entire visible spectrum. This platform enables high‐capacity, programmable, full‐gamut, and visually intuitive information encryption and display, providing a promising pathway for advanced, multidimensional anti‐counterfeiting and secure communication technologies.