Construction And Performance Of WO₃/Ag-Photosensitive Dye/NiO/TiO₂ Color-Changing Device

How to realize the rational utilization of energy and the effective protection of the ecological environment has become a huge challenge in today’s society.On this basis,the research on photochromic has attracted widespread attention.Photochromic devices made of typical electrochromic cathode material WO₃and photoanode material TiO₂have been widely used in smart windows,energy storage devices,displays and automotive rearview mirrors.How to prepare photochromic devices with better performance has become a research hotspot in recent years.In this paper,WO₃/Ag composite film was used as the photochromic cathode and TiO₂/NiO/CdS composite film was used as the photoanode to construct WO₃/Ag-CdS/NiO/TiO₂photochromic device.The specific research contents are as follows:（1）Firstly,WO₃nano-films were prepared on conductive glass（FTO）by hydrothermal method,and then WO₃/Ag composite films were prepared by hydrothermal method combined with electrodeposition method.The composition and morphology of WO₃and WO₃/Ag thin film samples were tested by XRD,SEM and EDS.The WO₃and WO₃/Ag thin film samples were tested by cyclic voltammetry,chronoamperometry,chronocoulometry,spectral transmittance and AC impedance,and the results were analyzed in detail.The results show that the reversibility,response time,optical modulation range and coloring efficiency of WO₃/Ag film samples are better than those of single WO₃nano-film.The WO₃/Ag composite film samples deposited with 5 s Ag have the best electrochromic performance.（2）Firstly,TiO₂thin films were prepared on conductive glass（FTO）by hydrothermal method.Then,TiO₂/NiO composite films were prepared by hydrothermal method combined with electrodeposition on the surface of TiO₂thin films with different lengths（5、10、15s）of NiO.Finally,TiO₂/CdS and TiO₂/NiO/CdS composite films were prepared by continuous ion layer deposition of CdS on TiO₂and TiO₂/NiO films.The structure and morphology of TiO₂/CdS and TiO₂/NiO/CdS composite films were characterized by X-ray diffraction and scanning electron microscopy.The LSV test,transient photocurrent test,spectral transmittance test and AC impedance test were carried out on TiO₂/CdS and TiO₂/NiO/CdS composite film samples,and the results were analyzed in detail.The analysis results show that the TiO₂/NiO/CdS composite films deposited with different lengths of NiO have better photoelectric conversion performance than the TiO₂/CdS composite film samples,and the TiO₂/NiO/CdS composite film samples deposited with 10 s NiO have the best photoelectric conversion performance.（3）The WO₃/Ag film with the best electrochromic performance was selected as the cathode of the photochromic device,and the TiO₂/NiO/CdS composite film with the best photoelectric conversion performance was selected as the photoanode of the photochromic device.The open-circuit voltage,short-circuit current density,fill factor,energy conversion efficiency,response time,optical modulation range and coloring efficiency of WO₃/Ag-CdS/NiO/TiO₂photochromic device were obtained by LSV test,cyclic voltammetry test and spectral transmittance,and compared with WO₃-CdS/TiO₂,WO₃/Ag-CdS/TiO₂and WO₃-CdS/NiO/TiO₂photochromic devices.The results show that the WO₃/Ag-CdS/NiO/TiO₂photochromic device has the best discoloration performance and photoelectric conversion performance compared with other devices.