Multichromatic superhydrophobic fluorescent carbon quantum dots for AI-enabled anti-counterfeiting and coating applications

Abstract

As of right now, most CDs that have been reported are still dissolved in solvents. Solid-state CDs usefulness is severely limited by their inability to stop aggregation-caused quenching (ACQ). In this work, superhydrophobic solid-state luminescent CDs with usual aggregation-induced emission (AIE) properties were made with acetic acid and dithiosalicylic acid (DTSA) via a simple solvothermal technique. Disulfide linkages are the main source of these CDs' AIE characteristics. They prevent surface groups on the CDs from rotating intramolecularly, which encourages solid-state fluorescence (SSF) during long-wave emission. Furthermore, emission tuning was achieved using ABT, APC, AHT, and HBT, leading to the successful synthesis of green, red, orange, and yellow AIE CDs, named YG-CDs, APC-CDs, YR-CDs, and CR-CDs, respectively. These CDs were then processed with a powder dusting technique to develop luminescent fingerprint powders. A Python program analyzed the fluorescence images of these LFPs, with the prime sample showing a 90% match score, indicating significant similarity to the standard control. Lastly, owing to their superhydrophobic nature, these multi-coloured CDs have promising applications in coatings, capable of imparting superhydrophobic properties to various substrates, including mild steel, cotton fibres, and lab coat cloth.