Figure 2.

(a) Steady-state photoluminescence spectra. (b) Time-resolved photoluminescence decay. (d) Periodic on/off photocurrent responses of ZnIn₂S₄ and Co₉S₈@ZnIn₂S₄. (c) Electrochemical impedance spectra Nyquist plots of ZnIn₂S₄, Co₉S₈@ZnIn₂S₄, and Co₉S₈@ZnIn₂S₄ under illumination. (e, f) optimized structural model (top view and side view) of the Co₉S₈@ZnIn₂S₄. (g, h) The charge density distribution of Co₉S₈@ZnIn₂S₄. (i) transfer process of the photogenerated electrons and holes in the Co₉S₈@ZnIn₂S₄ heterostructure.