Synergistic Chemical Enhancement in Near-Infrared-Excited Semiconductor Surface-Enhanced Raman Scattering via MXene-Modified Perovskites for Trace Organic Detection

In recent years, organic–inorganic hybrid perovskite materials have emerged as promising substrates for surface-enhanced Raman scattering (SERS) due to their high charge carrier mobility, which facilitates chemical enhancement via charge transfer. However, their performance, particularly in polycrystalline forms, is often limited by suboptimal energy-level alignment with probe molecules, which restricts the efficiency of photoinduced charge transfer (PICT) and thus the overall Raman signal enhancement. In this study, we address this limitation by incorporating a two-dimensional transition metal carbide/nitride (Ti 3 C 2 (OH) 2 MXene) into the perovskite matrix (CH 3 NH 3 PbI 3 ). While MXene alone exhibits notable SERS activity, its integration with perovskite significantly optimizes the interfacial energy-level alignment. This optimization enhances the PICT contribution, leading to a markedly stronger Raman signal from the MXene-perovskite hybrid compared to each component alone. Our results demonstrate a clear synergistic enhancement mechanism, rooted in improved energy alignment and facilitated charge transfer between the substrate and probe molecules. Our results demonstrate a clear synergistic enhancement mechanism rooted in improved energy-level alignment and facilitated charge transfer between the substrate and probe molecules. More importantly, this MXene-modified perovskite system is particularly well suited for near-infrared (NIR)-excited semiconductor SERS sensing, especially for the sensitive detection of trace organic molecules and dye-like analytes under 785 nm excitation.