The Preparation Of Zinc Oxides And Titanium Oxides Based Photoanodes And Their Application In Dye-Sensitized Solar Cells

Dye-sensitized solar cells（DSSCs）have attracted much attention mainly because of their advantages of low cost,simple preparation process,environmental friendliness and rich application scenarios.In a DSSC,the photoanode plays the role of electron transport and the support for dye adsorption,hence being very essential.Zinc oxide（Zn O）and titanium dioxide（Ti O₂）are the two most studied photoanode materials for DSSC application;and based on them,many fabrication procedures and post treatment have been reported.By now,there are still problematic issues related to them,such as high temperature annealing,long dye-adsorbing time for Ti O₂ photoanode and low performance of Zn O based DSSC.In this work,Zn O photoanode with abnormal double-layer structure and Ti O₂ photoanode via room-temperature process are investigated,details are following:（1）Effects of the abnormal Zn O double-layer on the photoanode for DSSCs are investigated.Via electrophoretic deposition（EPD）,Zn O nanoparticles with different sizes are used to prepare both single-layer and double-layer Zn O,which are used as photoanode for DSSCs.Results show that the layer fabricated by the large-size Zn O particles is better for electron transport and light scattering but unsuitable for dye loading,while the layer originating from small-size Zn O particles shows contrary results.Compared with single-layer Zn O devices,the performance of the double-layer devices is improved,which is mainly due to the balance of electron transport,light scattering and dye loading in the double-layer Zn O photoanode.The power conversion efficiency of the optimal DSSC device achieves 5.87%,which is among the high values in Zn O based DSSCs.It indicates that the abnormal Zn O double-layer structure is an effective strategy to improve the performance of Zn O devices.（2）Dyed Ti O₂ photoanodes are prepared by room-temperature processes for DSSCs.The Ti O₂/N719 composite is made by mixing Ti O₂ nanoparticles and the dye molecular of N719.Using this composite,dyed-photoanodes are fabricated via EPD or spray coating at room temperature,which are applied in DSSCs.The traditional processes such as high temperature annealing and immersion into dye solution have been removed by these methods,which reduces complicity of high temperature facility and the time cost of photoanode preparation,and can be expected to apply in flexible substrate.Compared with the device prepared by EPD,the devices prepared by spray coating show higher performance,which is attributed to more uniform surface of the photoanode.In the optimal DSSC device,the power conversion efficiency achieves 2.12%.