Ultrathin Non-van der Waals Chromium Sulfide: Liquid Phase Exfoliation, Characterization, and Self-Powered Photoelectrochemical Photodetector Application

In the search for new advanced 2D materials for technological applications and to expand the research of non-van der Waals (non-vdW) 2D electronic devices, this study presents a novel strategy for liquid phase exfoliation (LPE) of non-vdW Cr₂S₃ to produce Cr₂S₃ nanosheets (NSs). By utilizing N-methyl-2-pyrrolidone (NMP), bulk Cr₂S₃ is separated along the (001) plane, resulting in the formation of NSs with an average thickness of ≈3 nm. Various characterization techniques are applied to the Cr₂S₃ material before and after LPE. Subsequently, the obtained Cr₂S₃ NSs are integrated into a photoelectrochemical (PEC)-type photodetector (PD) to evaluate the photoelectric conversion efficiency under varying conditions. The findings indicate that the developed PD exhibits a distinct self-powered photodetection capability with a photocurrent (P_ph) of 39.5 nA cm⁻², a photoresponsivity (R_ph) of 622 nA W⁻¹, and a detectivity (D*) of 0.5 × 10⁷ Jones under 350 nm irradiation at 0 V. Moreover, the PD demonstrates rapid response time (0.06 s) and good long-term stability (over 15 days), thus providing valuable insight for the advancement of non-vdW Cr₂S₃-based optoelectronic devices.