Cu2O nanosheets via facile one-pot synthesis: high-performance SERS substrate with chemical enhancement for environmental sensing

For the first time, single-layer carbon dots (CDs) were used as capping agents to synthesize cuprous oxide nanosheets (Cu2O-NSs) as a high-performance surface enhanced Raman scattering (SERS) substrate, emphasizing their chemical enhancement mechanism. The Cu2O-NSs, synthesized using single-layer carbon dots as capping agents, exhibit uniform morphology and remarkable SERS activity, achieving an enhancement factor of 4.97 × 105 for crystal violet under 532 nm laser excitation. The SERS enhancement is primarily attributed to photoinduced charge transfer between the Cu2O-NSs and analyte molecules, as confirmed by energy-level alignment studies. The substrate demonstrates excellent signal homogeneity, batch-to-batch reproducibility, and long-term stability, with no significant signal attenuation over 60 days. These findings underscore the potential of Cu2O-NSs as a cost-effective and stable SERS substrate, with promising applications in chemical sensing and molecular detection.