Design and Synthesis of Long Persistent Luminescent Carbon Dots and Layered Double Hydroxides Composite Materials for Information Encryption

Abstract Long persistent luminescence (LPL) materials based on carbon dots (CDs) have emerged as promising candidates in advanced optoelectronics, but their practical development is severely hindered by aggregation-caused quenching (ACQ) and unstable triplet excitons in the solid state. Combining CDs with layered double hydroxides (LDHs) to construct composite materials for efficient LPL emission is of great significance. This research established high-performance CDs/LDHs composites through a unique strategy of heteroatom codoping and interfacial coordination engineering. Specifically, experimental results showed heteroatom doping and interfacial coordination can optimize the π-conjugation system of CDs and strengthen the interaction between CDs and LDHs, with significantly promoted LPL performance. Hence, YCDs/Mg2Al-LDHs and YCDs/Zn2Al-LDHs exhibited excellent LPL properties, including excitation-independent emission, large Stokes shifts, stable luminescence performance, and long afterglow durations (up to 8 s). Significantly, the composites possessed strong interfacial interactions and high practicability for dual-mode dynamic anti-counterfeiting and information encryption when formulated into fluorescent inks with poly(vinyl alcohol) (PVA). Together, the results of this research show that the strategy of heteroatom doping and interfacial coordination engineering is not only advantageous in conveniently constructing high-performance CDs/LDHs composites with advanced optical and LPL properties but also yields insights for effective monitoring and application of CDs-based LPL materials in related fields.