High-index facets and multidimensional hotspots in Au-decorated 24-faceted PbS for ultrasensitive and recyclable SERS substrates

Abstract

The rational manipulation of the morphology and architecture of plasmonic metal/semiconductor hybrids is quite important to improve their SERS performance by optimizing the electromagnetic enhancement and charge transfer. Herein, PbS–Au hybrids, in which PbS has 24 high-index {332} facets and Au has an adjustable size, are successfully prepared via a steerable hydrothermal strategy. The as-prepared PbS–Au hybrids exhibit high-index facets, strong visible-near-infrared light absorption, multi-interfacial plasmon coupling, abundant hotspots, and efficient charge transfer. As a result, the PbS–Au hybrids display largely improved SERS signals for detecting Rhodamine B compared with pure PbS and Au, which can be further improved by appropriately adjusting the amount and size of Au nanoparticles. The optimal SERS detection limit is lowered to 10⁻¹² M and the analytical enhancement factor can reach 5.1 × 10⁸. Moreover, for SERS, the prominent recycling and self-cleaning properties of PbS–Au hybrids under visible light irradiation are demonstrated, which are attributed to the broad plasmon absorption and fast charge transfer between Au and PbS. This work offers a potential way for developing efficient SERS substrates based on constructing metal/semiconductor architectures.