采用水热法制备了垂直生长的氧化镍(NiO)纳米片薄膜, 并利用电沉积法将普鲁士蓝(PB)负载到NiO纳米片薄膜上, 制备了新型的NiO/PB复合电致变色薄膜。利用X射线衍射仪(XRD)、场发射扫描电镜(SEM)对样品的晶型以及微观形貌进行了表征, 采用紫外–可见光光度计以及电化学工作站对NiO/PB复合薄膜的电化学和电致变色性能进行了研究和表征。结果表明: NiO/PB复合电致变色薄膜具有多孔结构和较大的比表面积, 可以增大电解质与电极材料的接触面积。PB成功负载到NiO薄膜表面, 使NiO/PB复合薄膜表现出较大的电流密度。相比于单层NiO薄膜, NiO/PB复合薄膜表现出更好的电致变色性能, 其光调制范围可以达到46%, 着色效率为141 cm2/C, 并且其着色时间可以缩短到5 s, 褪色时间为6 s。
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 cm2/C at voltage of 2.5 V, and fast response time of 6 s and 5 s for bleaching and coloration states, respectively.