A ratiometric fluorescence sensor for sensitive and selective dopamine detection based on carbon dots-gold nanoclusters hybrid Display omitted •A ratiometric fluorescence sensor based on CDots-AuNCs hybrid was designed for dopamine detection.•The sensor provided remarkable ratiometric fluorescence intensity change.•The sensor exhibited excellent sensitivity and selectivity.•Human serum samples were analyzed. In this work, a novel fluorescence resonance energy transfer (FRET)-based ratiometric fluorescent probe, carbon dots-gold nanoclusters hybrid (CDots-AuNCs), was fabricated for selective, sensitive and reliable sensing of dopamine (DA). This FRET probe is comprised of a two-fluorophore, where carbon dots (CDots) serve as the energy donor and gold nanoclusters (AuNCs) as the acceptor, with dual emission peaks at 420 nm and 610 nm under a single excitation wavelength of 380 nm. The addition of DA to this probe solution resulted in the fluorescence at 610 nm quenching, while the blue fluorescence at 420 nm recovering. By monitoring the change of ratiometric fluorescent intensity at 420 and 610 nm, the DA could be detected with the range from 5 to 180 nM and a limit of detection around 2.9 nM. Finally, the developed sensing method was successfully applied to DA determination in serum samples with satisfactory recoveries in the range of 95%–105%.