Monolayer Iron Oxychloride with a Resonant Band Structure for Ultrasensitive Molecular Sensing.

Two-dimensional layered materials (2DLMs) are expected to be next-generation commercial sensors for surface-enhanced Raman scattering (SERS) sensing owing to their unique structural features and physicochemical properties. The low sensitivity and poor universality of 2DLMs are the dominant barriers toward their practical applications. Herein, we report that monolayer iron oxychloride (FeOCl) with a naturally suitable band structure is a promising candidate for ultrasensitive SERS sensing. The generally boosted Raman scattering cross section of different analyte-FeOCl systems benefits from the resonant photoinduced charge transfer processes and strong ground-state interactions. In addition, the strong adsorption ability of monolayer FeOCl is crucial for rapid detection in practical applications, which is proven to be much better than those of conventional SERS sensors. Consequently, monolayer FeOCl enables diverse SERS applications, including multicomponent analysis, chemical reaction monitoring, and indirect ion sensing.