Design and Application of Laser‐Engraved Carbon Quantum Dots Rewritable Fluorescent Paper in Modern Exhibitions and Shows

With the growing demands for visual effects and interactive experiences in the exhibition industry, fluorescent patterns have gained attention for their unique visual impact and interactivity. The development of high‐resolution, low‐energy fabrication technologies with superior visual effects is crucial for this field. However, traditional methods are hindered by low resolution, photobleaching of organic dyes, and poor environmental adaptability, limiting their application in the exhibitions. This study utilizes urea and citric acid as raw materials to synthesize green‐emitting carbon quantum dots (CQDs) via a hydrothermal method. After solution dispersion, a stable aqueous dispersion is coated onto a piece of white filter paper to form a uniform, dense fluorescent layer. Based on the fluorescence quenching mechanism induced by the laser thermal effect, a low‐power (hundred‐milliwatt level) continuous‐wave laser beam is employed to selectively irradiate the coating. The localized thermal energy triggers structural changes in the CQDs, leading to irreversible fluorescence quenching in the irradiated regions. By precisely controlling the laser spot size and scanning path, high‐resolution dark patterns are etched onto a green fluorescent background, achieving high‐contrast patterned fluorescence modulation. This technology presents an eco‐friendly and cost‐effective patterning solution for diverse fields, including exhibitions, artistic performance, anti‐counterfeiting packaging, and museum displays.