Carbon dots with recoverable photo-bleaching for reusable UV detectors

Abstract Carbon dots (CDs) have emerged as a promising category of nanomaterials for sensing applications, primarily due to their cost-effectiveness, thermal stability, low toxicity, and unique luminescence properties. CDs sensors have been widely used in ion detection, but rarely in ultraviolet (UV) light detection. In this paper, we synthesized CDs via one one-step pyrolysis process. The exceptional thermal stability of CDs is exhibited by their ability to maintain 100 % initial photoluminescence (PL) intensity over a temperature range from 300 K to 700 K. The bleached CDs can recover almost 100 % of PL intensity through simple thermal treatment at 800 K. The photoluminescence of CDs retains approximately 80% of their initial intensity following five cycles of photo-bleaching and thermal recovery. Moreover, the fluorescence quenching degree maintains a good linear relationship with the UV photo-bleaching time. These indicate that CDs can be effectively used in reusable UV detectors.