Property Study Of Composite Structure Photoelectrode In Dye-sensitized Solar Cell

With the increasing depletion of traditional fossil energy,human society is facing an increasingly serious energy crisis.Solar energy is abundant,pollution-free and not limited by the geographical environment,and gradually becomes the main research object to solve the energy problem.In all solar cells,Dye-sensitized solar cells?DSSCs?have attracted extensive attentions from the researchers all over the world due to its low production cost,simple preparation process,high conversion efficiency,and environment friendly properties.TiO₂ photoanode is an important part of DSSCs,and is closely related to light harvesting,electron injection and collection.The performance of photoanode has direct influence on the photoelectric performance of DSSCs.Therefore,in order to further improve the performance of DSSCs,it is necessary to modify and optimize the TiO₂ photoanode.In this paper,on the one hand,TiO₂ nanotube arrays were optimized by changing the oxidation conditions to meet the requirements of photoanode.On the other hand,flower-like TiO₂ film was introduced as a diffuse layer to enhance the utilization ratio of sunlight.The main contents and results could be summarize as follows:?1?The TiO₂ nanotube arrays were synthesized by anodic oxidation under other invariable conditions,TiO₂ nanotube arrays with different morphologies were obtained by changing the oxidation time,electrolyte concentrations.Double-layer composite films consists of TiO₂ nanotube arrays as overlayer and P25 nanoparticle as underlayer were designed as the photoelectrodes of dye-sensitized solar cells.The photoelectric properties of TiO₂ photoanodes under different conditions are compared and studied by XRD,SEM,TEM and UV.The experiment results demonstrate that the length and the diameter of TiO₂ nanotube arrays are closely related to oxidation time and electrolyte concentrations.The double-layer composite film DSSCs achieved the highest conversion efficiency of 4.20%when the oxidation time is 18h,electrolyte concentrations is 0.3wt%.?2?The flower-like TiO₂ were prepared by hydrothermal treatment and three-layer composite film consists of flower-like TiO₂ as overlayer,TiO₂ nanotube arrays as interlayer and P25 nanoparticle as underlayer was fabricated.Then we have investigated and compared the photoelectric conversion properties of DSSCs based on three-layer structure photoelectrode and double-layer film photoelectrode by XRD,SEM,TEM and UV.The experiment results demonstrate that the crystal structure of flower-like TiO₂ is rutile.And the photoelectric performance of three-layer composite film electrodes is decided by two kinds of TiO₂.Because of the existence of flower-like TiO₂,the three-layer composite film has stronger light scattering ability,and DSSCs based on three-layer structure exhibit a high power conversion efficiency of 6.48%.