Abstract

Abstract Few‐layer tin (Sn)‐based nanosheets (NSs) with a thickness of ≈2.5 nm are successfully prepared using a modified liquid phase exfoliation (LPE) method. Here the first exploration of photo‐electrochemical (PEC) and nonlinear properties of Sn NSs is presented. The results demonstrate that the PEC properties are tunable under different experimental conditions. Additionally, Sn NSs are shown to exhibit a unique self‐powered PEC performance, maintaining a good long‐term stability for up to 1 month. Using electron spin resonance, active species, such as hydroxyl radicals (·OH), superoxide radicals (·O 2 − ), and holes (h + ), are detected during operations, providing a deeper understanding of the working mechanism. Furthermore, measurements of nonlinear response reveal that Sn NSs can be effective for all‐optical modulation, as it enables the realization of all‐optical switching through excitation spatial cross‐phase modulation (SXPM). These findings present new research insights and potential applications of Sn NSs in optoelectronics.