Application Research Of Polyoxometalate-based Electrochromic Composite Films In Photovoltaic Devices And Fluorescent Switches

Polyoxometalates,referred to as POMs,are a class of multinuclear complexes and also an important branch of inorganic chemistry.As a metal oxide cluster with nanostructures,it has great prospect of application in electrochromism due to its unique and attractive structure and excellent electrochemical performance.In this work.,heteropolyacid K10[?2-P2W17O61]·20H2O(P2W17)was used as precursor.P2W17-TiO2 composite films with electrochromic properties were successfully prepared by electrodeposition and applied to dye sensitized solar cell and a photoelectrochromic device was assembled.A bifunctional composite film P5W30-Eu-TiO2 with electrochromic and fluorescent switching properties was successfully prepared using heteropolyacid(NH4)14[NaP5W30O110]·31H2O(P5W30)electrodeposition to Eu-doped TiO2 film.They were studied by X-ray powder diffraction,scanning electron microscopy,ultraviolet-visible spectrophotometer,fluorescence spectrophotometer et al.This article is divided into four parts:The first chapter is the preface.It mainly introduces the related research progress of POMs in the field of electrochromic,dye-sensitized solar cells and fluorescent switches,and also explains the significance of this paper.The second chapter mainly introduces the application and performance of polyoxometalate P2W17-TiO2 composite film on photoelectrochromic device.The polyoxometalate-TiO2 composite film was characterized by scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FT-IR).The performance of photochromic device was studied by 1-V curve test,photocurrent test and transmittance test.The third chapter mainly introduces the preparation of polyoxometalate Eu-TiO2-P5W30 electrochromic and fluorescent switch bifunctional composite film.The prepared P5W30-Eu-TiO2 composite film was characterized by scanning electron microscopy(SEM),X-ray powder diffraction(XRD)and Fourier transform infrared spectroscopy(FT-IR).The electrochromic performance and fluorescent switching performance of the composite film was studied by using an electrochemical workstation with an ultraviolet-visible spectrophotometer and a fluorescence spectrophotometer,respectively.The fourth chapter is the conclusion and prospect.It mainly summarizes the contents of the previous introduction and prospects for the development of polyoxometalate.