ReS Nanoflowers-Assisted Confined Growth of Gold Nanoparticles for Ultrasensitive and Reliable SERS Sensing.

ReS, as a new member of transition metal dichalcogenides (TMDCs), has emerged as a promising substrate for semiconductor surface-enhanced Raman spectroscopy (SERS) due to its unique optoelectronic properties. Nevertheless, the sensitivity of the ReS SERS substrate poses a significant challenge to its widespread application in trace detection. In this work, we present a reliable approach for constructing a novel ReS/AuNPs SERS composite substrate, enabling ultrasensitive detection of trace amounts of organic pesticides. We demonstrate that the porous structures of ReS nanoflowers can effectively confine the growth of AuNPs. By precisely controlling the size and distribution of AuNPs, numerous efficient and densely packed "hot spots" were created on the surface of ReS nanoflowers. As a result of the synergistic enhancement of the chemical and electromagnetic mechanisms, the ReS/AuNPs SERS substrate demonstrates high sensitivity, good reproducibility, and superior stability in detecting typical organic dyes such as rhodamine 6G and crystalline violet. The ReS/AuNPs SERS substrate shows an ultralow detection limit of 10 M and a linear detection of organic pesticide molecules within 10-10 M, which is significantly lower than the EU Environmental Protection Agency regulation standards. The strategy of constructing ReS/AuNPs composites would contribute to the development of highly sensitive and reliable SERS sensing platforms for food safety monitoring.