Quantum Dot Sensitized TiO₂ Nanoarray Photoanode: Preparation And Photoelectrical Property Research

As a kind of novel solar cells, quantum dots sensitized solar cells（QDSSCs） have attracted great attention due to simple fabrication processing, high theoretical efficiency and so on. However, because of the limitation of materials and interface structures, the efficiency of QDSSCs is still behind its theoretical efficiency and doesn’t meet the requirement of commercialization. Therefore, optimization the structure of the solar cell, introduction of new materials, and improving the structure of interface have been studied for enhancing the efficiency of QDSSCs.In present thesis, we systematically studied the effect of photoanode’s structure on QDSSCs’ efficiency by optimizing the thickness of mesoporous TiO₂ film, preparing TiO₂ nanorod array structure, fabricating g-C₃N₄/TiO₂ composite structure. These results provided experimental reference for further development of QDSSCs.The main results can be summarized as follows:1. TiO₂ nanocrystalline porous film was prepared by spin-coating method. CdS QDs sensitized TiO₂ porous film was prepared by successive ionic layer absorption and reaction（SILAR） method. CuS counter electrode was prepared by chemical bath deposition（CBD） method. The results showed the thickness of TiO₂ porous film could affect the QDSSC’s photoelectric conversion performance.The performance of QDSSC was the best when the thickness of TiO₂ film was 8 μm.2. TiO₂ nanorod array was prepared by hydrothermal method on the FTO glass. The morphology was studied by different preparation conditions. The results show that TiO₂ nanorod array can significantly improve the Voc and Jsc of QDSSCs. In addition, by combining nanorod array and mesoporous film of TiO₂, sensitized by CdS and CdSe QDs, the efficiency of solar cell is further enhanced to 4%.3. g-C₃N₄/TiO₂ three-dimensional constructure photoanodes was prepared by spin-coating and annealing method. We obtained CdS QDs sentsized TiO₂ nanorod/g-C₃N₄ three-dimensional constructure solar cell and studied its photovoltaic performance. The results showed that the efficiency of CdS QDs sentsized TiO₂ nanorod/g-C₃N₄ three-dimensional constructure solar cell was obvious improved higher because of appropriate energy band structure. The efficiency was enhanced from 2.28% to 2.66%.