Construction And Performance Of WO₃/Cu-Photosensitive Dye/NiO/TiO₂ Color-changing Device

In the modern society with increasingly serious environmental pollution and energy crisis,energy conservation and environmental protection have become two major themes that need to be seriously considered in social development.According to research,the energy consumption caused by refrigeration and heating in the use of buildings in China has occupied a very alarming proportion.In the process of solving this problem,researchers began to use photoelectrochromic（PECDs）smart windows.The photoelectrochromic smart window constructed by a typical WO₃color-changing cathode and a dye-sensitized TiO₂photoanode can effectively adjust light and heat through color conversion,and does not require external power supply.In this paper,WO₃-based electrochromic films,dye-sensitized TiO₂photoanodes and their constructed photoelectrochromic devices are the main research objects to improve the performance of photoelectrochromic devices.The performance of thin films and photoelectrochromic device is improved by means of composite materials on the color-changing cathode film and photoanode film.The WO₃/Cu electrochromic cathode,TiO₂/Ni O/Cd S photoanode,WO₃/Cu-Cd S/Ni O/TiO₂photoelectrochromic device are the main research objects.The specific research contents are as follows:（1）Firstly,WO₃films were prepared on conductive glass（FTO）by hydrothermal method,and then WO₃/Cu composite films were prepared by electrodeposition.The electrochromic properties were optimized by adjusting the electrodeposition time of Cu（2 s,4 s,6 s）.The WO₃/Cu composite films were characterized by XRD,XPS,SEM and EDS.The WO₃/Cu composite films were tested by cyclic voltammetry,chronocoulometry,spectral transmittance,response time and AC impedance.The results show that the reversibility,light modulation range,response time and coloring efficiency of WO₃/Cu composite film are better than those of WO₃film,and the WO₃/Cu composite film electrodeposited for 4 s has the best electrochromic performance.（2）Firstly,TiO₂thin films were prepared on conductive glass（FTO）by hydrothermal method,and then TiO₂/Ni O composite films were prepared by electrodeposition.The photoelectric conversion performance was optimized by adjusting the electrodeposition time of Ni O（5 s,10 s,15 s）.Finally,TiO₂/Ni O/Cd S photoanode was prepared by continuous ion layer deposition.The TiO₂/Ni O/Cd S photoanode was characterized by XRD,SEM and EDS.The TiO₂/Ni O/Cd S photoanode was subjected to linear cyclic voltammetry（LSV）test,transient photocurrent test,spectral transmittance test and AC impedance test under illumination.The results show that the TiO₂/Ni O/Cd S photoanode with Ni O electrodeposition time of 10 s has the best photoelectric conversion performance.（3）WO₃/Cu-CdS/NiO/TiO₂photoelectrochromic devices were constructed by using WO₃/Cu composite film with the best electrochromic performance and TiO₂/Ni O/Cd S photoanode with the best photoelectric conversion performance as the color changing cathode and photoanode,respectively.The open circuit voltage,short circuit current density,fill factor,photoelectric conversion efficiency,response time,optical modulation range and coloring efficiency of WO₃/Cu-Cd S/Ni O/TiO₂photoelectrochromic device were obtained by linear cyclic voltammetry（LSV）test,spectral transmittance test and response time test,and compared with WO₃-Cd S/TiO₂photoelectrochromic device.The results show that the performance of WO₃/Cu-Cd S/Ni O/TiO₂photoelectrochromic device is better than that of WO₃-CdS/TiO₂ photoelectrochromic device.