Photoanodes In High-performance Dye-sensitized Solar Cells

Nowadays,people are facing two critical challenging issues:environmental pollution and the lack of renewable energy resources,so developing an environment-friendly and renewable energy resource is of great urgency.As a promising alternative for conventional expensive silicon-based solar cells,dye-sensitized solar cells（DSSCs）have attracted numerous attentions in the past decades because of their low cost,high power generation efficiency,and no harm to the environment.This paper has mainly carried on the following part of work based on the current development of DSSC.Photoanodes with sub-micrometer cavities of different sizes and ratios were easily fabricated by burning off the polystyrene sub-micrometer spheres（PSSs）embedded in TiO₂ paste.The optimized performance of the fabricated dye-sensitized solar cells was remarkably 48%higher than that of pristine TiO₂ DSSCs without sub-micrometer cavities in control group.TiO₂ nanowires（NWs）were obtained by hydrothermal method and assembled in DSSCs in this article.Comparing the energy conversion of DSSCs consist of different ratios of nanowires and nanoparticles,authors have gained the optimal ratio in the cells and achieved the highest energy conversion,which is 14%higher than pristine TiO₂ nanoparticles cells.A novel three-level hierarchical TiO₂ nanostructure with the first level made up of nanourchins（NUs）,the second level composed of NWs,and the third level made up of nanoparticles（NPs）was synthesized using an ion-modified hydrothermal method and subsequent TiCl₄ treatment.The hierarchical structure based DSSCs have achieved an higher conversion efficiency（η=3.25%）than that of their counterpart,pure NW based DSSCs,which is attributed to the larger surface area and stronger light scattering effect of this new three-level hierarchical nanostructure.A proof-of-concept experiment involving with an integrated self-powered color-changing system consisting of TiO₂ NWs based sandwich DSSCs and electrochromic devices（ECD）were firstly designed and demonstrated.As the sunlight illuminates on the entire system,DSSCs generate the electrical power and turn the ECD to darker color,dimming the lights;while switching the connection polarity of the DSSCs,the lighter color might be regained,implying the potential application of this self-powered color-changing system as the next generation sun glasses and smart windows...