Fig. 3. (a) The ultraviolet–visible diffuse reflection spectra (UV/Vis DRS), the inset shows the corresponding Tauc plots, (b) electronic band structures, (c) transient photocurrent response, (d) electrochemical impedance spectroscopy (EIS), (e) the steady-state photoluminescence (PL) measurements, and (f) time-resolved photoluminescence (TR-PL) spectra of Tf-TAPB-COF, Tf-TAPP-COF, Tf-TAPPM-COF, and Tf-TAPT-COF.