Preparation Of Double-layer Titanium Dioxide Photoanode Film And Its Application In Dye-sensitized Solar Cells

Energy is the cornerstone of global economy development.With the increasing exhaustion of traditional fossil fuels,green renewable energy will become the main theme of the development of world energy.Solar photovoltaic devices begin to get widespread attention.In particular,dye-sensitized solar cell?DSSC?has been extensively studied for its low cost,simple fabrication process,high theoretical photoelectric conversion efficiency,stable performance and no environment pollution.However,in practical applications,the photoelectric conversion efficiency of DSSC is low.How to improve efficiency is the problem we need to solve.Semiconductor TiO₂ is the main applied photoanode material of dye-sensitized solar cell.It is with characteristics of abundant raw materials,low cost,chemical inert and biological non-toxic.Improving the performance of TiO₂ photoanodes is very important to enhance the photoelectric conversion efficiency of dye-sensitized solar cells.In this paper,it is mainly undertaken from the optimization of the TiO₂ photoanodes' structures to improve the light absorption capacity and electron transport rate,further increasing the photoelectric conversion efficiency of dye-sensitized solar cells.The specific research contents are as follows:?1?Study on DSSC with enhanced photoelectric properties by surface plasmon resonance of Au/Ag nanoparticles/nanowires.Two-dimensional TiO₂ nanosheets,three-dimensional TiO₂ microspheres and three-dimensional TiO₂ hollow spheres were prepared by hydrothermal method.Novel double-layer TiO₂ films were prepared by the method of doctor blade.The bottom layer is composed of anatase TiO₂ nanoparticles with small grain size as a bonding layer.The top layer is a multifunctional layer,including microspheres,hollow spheres,P25 and nanosheets.The Au/Ag nanostructures were introduced into the top layer of TiO₂ photoanode films and applied in DSSCs.The effects of gold nanoparticles?AuNPs?,silver nanoparticles?AgNPs?,gold nanowires?AuNWs?and silver nanowires?AgNWs?on the photoelectric properties of dye-sensitized solar cells were systematically investigated.The results show that the power conversion efficiency of the cells is improved by doping of Au/Ag nanostructures.The dye-sensitized solar cell based on TiO₂-AgNW photoanode film yields the highest power conversion efficiency?PCE,??of 5.74% and the short circuit photocurrent density?Isc?of 13.02 mAcm-2,representing a 25.3% improvement in power conversion efficiency compared with the pure cell?4.58%,11.83 mAcm-2?.The main reasons for enhancement of Isc and ? are: improved electron transport rate;a further improvement of light absorption and light scattering caused by the local surface plasmon resonance?LSPR?effect.?2?Dye-sensitized solar cells based on double-layer composite film with enhanced photovoltaic performance.One-dimensional TiO₂ nanorod arrays,two-dimensional TiO₂ nanosheets and three-dimensional TiO₂ microspheres were prepared by hydrothermal method.Novel double-layer photoanode films of TiO₂ nanorod arrays/nanosheets-microspheres were prepared by the method of doctor blade and applied in dye-sensitized solar cells?DSSCs?.The influence of the mass percentage of TiO₂ nanosheets and microspheres on the photoelectric properties of the cells was investigated.The results show that the cells have optimum photoelectric properties when the mass percentage of TiO₂ nanosheets is 50%,and the photoelectric conversion efficiency is 1.71%.It is because that the cell with 50% nanosheets has good light absorption characteristics,smaller carrier recombination rate and faster electron transport rate.In this paper,two kinds of double-layer TiO₂ photoanode films with different structures were prepared and applied in dye-sensitized solar cells.The effects of structure,composition and morphology of the double-layer photoanode films on the photovoltaic properties of cells were investigated.This paper will provide a new research basis for the application of double-layer TiO₂ photoanode films in DSSCs.