Synthesis and optimization strategy for enhancing SERS performance of Cu2O nanoparticles

The sensitivity and stability of SERS substrates are critical in surface-enhanced Raman scattering (SERS) spectral applications. The present study describes the synthesis of Cu 2 O nanoparticles using a facile chemical method. It was observed that both glucose and NaBH 4 , employed as reducing agents, exerted significant influence on the particle size. Notably, NaBH 4 exhibited enhanced efficacy in producing nanoscale particles. Furthermore, the structural characteristics of the sample were significantly influenced by the concentration of the reducing agent NaBH 4 ; an excessive concentration resulted in the emergence of metal copper. The Cu 2 O nanoparticles, obtained through a suitable reduction process using NaBH 4 , exhibited significant SERS activity, indicating a strong chemical interaction between Cu 2 O and rhodamine 6G (R6G) molecules. The N-doped Cu 2 O nanoparticles with varying proportions were synthesized. Raman spectra analysis revealed that the 2%N–Cu 2 O nanoparticles exhibited the most significant enhancement effect. These findings suggest that doping represents an effective approach to enhance the SERS activity of semiconductor substrates. In addition, in-situ reduction reaction was employed to synthesize Cu 2 O/Ag composite nanoparticles, which exhibited outstanding SERS activity and enabled the detection of 10 −9  M R6G. The observed enhancement is mainly attributed to the synergistic effects arising from the electromagnetic enhancement provided by Ag nanoparticles and the chemical enhancement offered by Cu 2 O. This research provides a simple and cost-effective method for preparing Cu 2 O-based SERS substrates with excellent performance, offering valuable insights and approaches for enhancing SERS performance in the future.