Optimization of h-BN/Ag/Ag₂O heterostructure by high temperature annealing and its surface-enhanced Raman scattering performance

Abstract

As a commonly used food additive, synthetic dyes are widely used in foods such as beverages, sweets and dairy products, and in the food processing process, excessive use of synthetic dyes may induce cell mutations, children's hyperactivity, genetic diseases and even cancer, posing a great threat to human health. As a fast, cheap, stable, ultra-sensitive and accurate detection method, SERS detection can reflect rich molecular fingerprint information through the vibration of the analyte, and accurately determine the trace amount of synthetic dyes in the actual environment. The metal/semiconductor heterostructure formed by the combination of plasmon metal and semiconductor is advantageous for the enhancement of photoinduced charge transfer efficiency (PICT), and has obvious advantages in the study of surface-enhanced Raman scattering. In this paper, the prepared hybrid substrate is annealed to further improve the surface-enhanced Raman scattering activity. Initially, high-density and monodisperse silver/silver oxide (Ag/Ag<sub>2</sub>O) nanoparticles were loaded onto two-dimensional hexagonal boron nitride (h-BN) nanosheets. On this basis, by annealing the system at high temperature, an efficient charge transfer channel is constructed, which greatly improves the PICT efficiency and chemical enhancement (CM). It was confirmed by experiments that the SERS signal intensity of h-BN/Ag/Ag<sub>2</sub>O material annealed at 320 ℃ with crystal violet (CV) as probe molecule was significantly increased by 18 times compared with unannealed material，enhancement factor (EF) reached 16.3145×10<sup>7</sup>. Finally, based on the excellent SERS property of h-BN/Ag/Ag<sub>2</sub>O 320℃ annealing composite, the SERS detection of food additive patent Blue V (PBV) was conducted in this paper. The results showed that the lowest detection concentration could reach 10<sup>-12</sup> M, and the trace detection of synthetic dye PBV was realized. It has excellent spatial uniformity and anti-interference ability, which is of great significance in the actual scene detection of PBV. The h-BN/Ag/Ag<sub>2</sub>O 320 ℃ annealed composite constructed in this paper has both physical and chemical enhancement, and has significant advantages in ultra-low sensitive SERS detection of food additives.