| The world’s energy problems are mainly the contradiction between the shortageof energy and the demand and the contradiction between the energy utilizationand theenvironment. The excessive exploitation and utilization has caused thenon-renewableenergy to the verge of extinction. Therefore, People turned their attention to the new,clean and renewable energy. However, solar energy is one of hailed renewable energywith endless and clean. The optical energy is converted into a form of availableenergy on the nature of the solar energy, for example, electric energy and thermalenergy. The utilization of solar energy is the production of the solar cells which baseon photoelectric conversion principle, and is widespread concerned with hightheoretical conversion efficiency. Since the development of solar cells, dye sensitizedsolar cells (DSSCs) with prominent superiority and recognized high photoelectricconversion efficiency have been received widespread attention among the thirdgeneration of photovoltaic devices, and considered to be one of the most promisingcandidates in solar cells.In DSSCs structures, photoanode plays the following effects: Firstly, as a carrierof the dye, secondly, as a medium for scattering of the incident light, thirdly, as aplatform of the teleportation. Therefore, require it to have a large specific surface area,a temperate size and structure, and a good conductivity. As the preferred photoanodefilm materials of DSSCs, TiO2has the proper position of the band gap and energylevels, and has the excellent characteristics above. In recent years, the design andfabrication of hierarchical structure TiO2based on large specific surface area andexcellent optoelectronic properties for DSSCs are becoming research focus. In this paper, micro/nano-TiO2materials synthesis, fabrication and assembly processes ofDSSCs devices for technical support. In order to construct high specific surface areaand the strong scattering capacity of TiO2photoanode films structure. Thus achievethe ultimate goal for providing an experimental basis and theoretical guidance for therealization of high-performance photoanode films and efficient TiO2-based DSSCs.The specific studies include:(1) Commercial P25TiO2powder was used as a precursor, when the alkalisolution was without and with adding hydrogen peroxide (H2O2), the commercialTiO2nanoparticles (P25) were modified under hydrothermal conditions, in order toincrease the surface area and the optoelectronic properties of TiO2. To prepare3Dnanomesh structure and urchin-like structure TiO2nanomaterials with high specificsurface area (424m2g-1and392m2g-1). Prepared TiO2hierarchical structures wereused as scattering layer, P25was used as transparent layer, P25+hierarchicalstructures were used as blended layer to construct the new types of TiO2photoanodestructure, the energy conversion efficiency of DSSCs with these two structurematerials and special structure photoanodes have47%and36%increase comparedto those of P25electrode, respectively.(2) Combine the hydrothermal growth and alkali corrosion methods, aninnovative development of novel double layered photoanodes made of hierarchicalTiO2micro-corollas as the overlayer and TiO2nanoforest as the underlayer (TC-BF)on FTO (Fluorine-doped tin oxide) glass substrate for dye-sensitized solar cells(DSSCs) was developed. The different morphologies TC-BF double layeredphotoanodes with different conditions are characterized by SEM, TEM and XRD, andthen DSSCs devices are assembled and the photoelectricity characteristics are furtherdiscussed. It was found that the maximum density nano-forest photoanode had thehighest energy conversion efficiency, which due to its the most superior performanceon light scattering, dye adsorption and electronic transmission.(3) Tetra-n-butyl Titanate (TBT) was used as the titanium source, anddiethylenetriamine (DETA) was used as the structure-directing agent, core-shell structure materials with mesoporous were synthesized through hydrothermal method.Prepared TiO2above were used as scattering layer, P25was used as transparent layer,and the photoanodes were built with them. The optical path of the incident light iscontrolled by using core-shell structure and this unique structure act as a―light trap‖,scattering effect improved significantly. Meanwhile, the pores of mesoporousstructure can provide more dye adsorption, base on the factors above, thephotoelectricity performances of DSSCs devices are enhanced greatly. The energyconversion efficiency of the DSSCs had a38%increase compared to those of P25electrode. |
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