Figure 3.

a) Cyclic voltammograms and in situ transmittance at 500 nm of Ni‐BTA nanowire film in 1 m KOH electrolyte at a scan rate of 10 mV s⁻¹ in the potential range of 0–0.6 V versus Ag/AgCl. b) Transmittance spectra of Ni‐BTA nanowire film in the initial, bleached (0 V vs Ag/AgCl) and colored (0.6 V vs Ag/AgCl) states between the wavelength region of 300–1100 nm. c) Photographs of Ni‐BTA nanowire film in the initial, bleached, and colored states. d) Solar irradiance spectra converted from the measured transmittance spectra of Ni‐BTA nanowire film. e) In situ optical responses of the film with size of 4 cm² under the applied potential square‐wave of 0 and 0.6 V versus Ag/AgCl for Ni‐BTA nanowire film for 60 s per step test at 500 nm. f) Optical density as a function of the charge density during coloring process at 500 nm.