Sustainable Red Emissive Carbon Dots Derived From Red Beans for Pb2+ Probe

Carbon dots (CDs) have emerged as a promising class of fluorescent nanomaterials. This study reports a green synthesis of red fluorescent CDs (R-CDs) using an inexpensive and sustainable carbon source – red beans. The R-CDs exhibits excellent optical properties and outperforms many other reported red-emitting CDs in terms of high quantum yield (20.4%) and photostability. The R-CDs show excitation-independent emission behavior, indicating unique luminescent centers. The R-CDs display remarkable dispersibility, salt-resistance and temperature stability. Additionally, the R-CDs demonstrate high selectivity toward Pb²⁺ detection with a low detection limit of 0.8 µM, expanding their application as fluorescent probes. This work establishes an effective strategy for synthesizing high-quality R-CDs using sustainable carbon sources, providing a new avenue for tailoring CDs with tunable fluorescence properties for broader applications in sensing and imaging.