Tunable energy level induced fluorescence enhancement in copper functionalized silicon quantum dots for highly selective detection of bisulfite

Bisulfite plays crucial roles in various environmental pollution and toxicological effects of atmospheric particles events. Selective and highly sensitive sensing of bisulfite in environment is of great significance for particulate matter formation research. In this work, we purposely synthesized copper functionalized silicon quantum dots (Cu-SiQDs) with small energy level, which can specially react with bisulfite resulting significant fluorescence enhancement, and a direct sensing platform for bisulfite was constructed in atmospheric particulate matters. Additionally, the fabricated assay had a broad linear range of 1–80 μM and low detection limit (0.82 μM). Through amounts of experiments and analysis, the interaction mechanisms between Cu-SiQDs and the enhancer bisulfite was proposed that a complex shell was formed on the surface of Cu-SiQDs, which modulated its energy band gap and accelerated electron transfer. The study provides a new sight of modified metal-free QDs nanostructure for highly selective luminescence detection in complex samples.