Fig. 8 (a) Time-photocurrent response and (b) EIS curves of ITO/ZCS, ITO/ZCS/CoP, ITO/ZCS/Co3O4 QDs and ITO/O/ZCS/P-3 electrodes; (c) Steady-state PL spectra and (d) Time-resolved PL emission decay curves of ZCS, ZCS/CoP, ZCS/Co3O4 QDs, and O/ZCS/P-3.