Preparation and Properties of NiO/PB Hybrid Electrochromic Film

The vertically grown NiO hierarchical nano-structures were synthesized on FTO-coated glass using a crystal-seed-assisted hydrothermal technique. The NiO/PB film was obtained by the electrodeposition of PB on the NiO film. The crystal structures of the synthesis products were identified by X-ray diffraction technique and the microstructure and morphology of the films were characterized by field emission scanning electron microscope. The electrochemical property experiments were performed with an electrochemical workstation and the optical properties of the devices were recorded by Lambda 950. The NiO/PB film is composed of nanosheets and thus forming a porous structure. The porous structure could accelerate the interface electron kinetics between the film and electrolyte because its large electrochemical active area. Higher charge-insertion density of the NiO/PB film over the same period indicates faster kinetics, which means that the NiO/PB film possesses fast electrochemical response. Compared with the single NiO film, the NiO/PB film exhibits highly enhanced electrochromic performances, i.e. high optical modulation(46% at 700 nm without background correction), high coloration efficiency of 141 cm~2/C at voltage of 2.5 V, and fast response time of 6 s and 5 s for bleaching and coloration states, respectively.