Facile preparation of Cu2-xS supernanoparticles with an unambiguous SERS enhancement mechanism

Surface-enhanced Raman scattering (SERS) techniques benefit from the development of various substrates ranging from noble metal to semiconductor materials. Semiconductor substrates have been assumed to construct more specific structures and designable surface chemistry than noble metal substrates. Therefore, the development of semiconductor substrates may lead to the selective recognition of target molecules, more stable SERS spectra, and even low-cost fabrication of SERS substrates. In this paper, we disclose semiconductor supernanoparticles formed by a self-limiting assembly process with stable properties, easy scale-up fabrication, and high SERS enhancement. The detected concentration of analytes reaches as low as 10−8 M. The built-in hotspots and self-doping in suprananoparticles provide strong electromagnetic enhancement, and the molecular resonance and charge transfer with the target molecule contribute to chemical enhancement. Discrete dipole approximation simulation was used to further confirm the SERS enhancement mechanism. Cu2-xS supernanoparticles paved a new way to construct novel semiconductors with SERS activity.