Electrochemical study of MoO₃ and MoO₃:Li⁺ thin films: the influence of lithium ions

MoO₃ and MoO₃:Li⁺ thin films were deposited on FTO glass substrates using the sol–gel dip-coating technique. MoO₃ and MoO₃:Li⁺ films consisting of different thicknesses were studied by cyclic voltammetry (CV), chronoamperometry, and chronocoulometry. They also were characterized by SEM-FEG and AFM microscopies, X-Ray (XRD), and FTIR and UV–Vis spectroscopies. It was found that AFM surface roughness increased from 22 for MoO₃ to 167 nm for MoO₃:Li⁺ thin films, XRD patterns did not show any sharp peaks of MoO₃ confirming these films’ amorphous nature, and UV–Vis provided these films’ band gap values within the range of 3.64–3.70 eV. The Li⁺ diffusion coefficients were 5.47 × 10^–10 and 4.92 × 10^–9 cm².s⁻¹, and the bleached/colored states transmissions were of 73/59 and 71/44% for MoO₃ and MoO₃:Li⁺, respectively. Overall, the doping MoO₃ with lithium improved its electrochemical and electrochromic characteristics, making it a promising candidate for electrochromic device applications.