Polydopamine modified Nd-doped TiO2 films for improved electrochromism and energy storage

Electrochromic materials can show reversible optical changes under the small applied voltages, which have the great application prospects in smart window, energy storage, thermal control fields. In the practical application of electrochromic materials, fast responsiveness and stable periodicity are urgently needed. In this study, the nanoporous Nd-doped TiO2 (TNO) films are synthesized by the hydrothermal method, and then polydopamine (PDA) is coated on the surfaces of TNO films to prepare TNO-Pt films (t = 15, 30, 60 and 120). TNO-Pt films have the wider transmittance modulations and larger surface capacitances than that of TNO film. Moreover, TNO-Pt films have shorter response times and higher cycle stability due to PDA films enhance the interface ion transfer properties and electrochemical stability of nanoporous TNO films. In particular, the coloring and bleaching times of the TNO-P60 film is 12.4 and 18.3 s, and retained 91.7 % of the initial transmittance modulation (70.3 %) after 2000 cycles. In addition, the surface capacitance of TNO film modified by PDA can be risen to 238 %. Therefore, TNO-Pt films can be used as one candidate material for electrochromic energy saving and storage window.