Synthesis of Graphene Quantum Dots (GQDs) from Paddy Straw for Bilirubin Detection

This work reports the synthesis of blue-emitting graphene quantum dots (GQDs) with an average diameter of 3.8 ± 0.5 nm from paddy straw, a sustainable biomass resource, via hydrothermal synthesis. These GQDs demonstrate excellent performance in bilirubin (BR) detection. The GQD photoluminescence (PL) intensity exhibits a proportional decrease with increasing BR concentration, indicating efficient quenching. The limit of detection for BR reaches a low value of 87.9 nM, highlighting the high sensitivity and selectivity of the GQD-based sensor. The observed quenching likely arises from a combined mechanism involving static quenching due to GQD-BR complex formation, inner filter effect (IFE), and Förster resonance energy transfer facilitated by spectral overlap.