Study on Belt-type ZnO Photoanode for Dye-sensitized and Quantum-dot Sensitized Solar Cells
|Course||Materials Science and Engineering|
|Keywords||Dye-sensitized solar cells Quantum-dots sensitized ZnO nanobelt structure Electrodeposition CdS quantum dots|
Dye-sensitized solar cell （DSC）, a new type solar cell, will become a powerful competitor with silicon-based solar cells, owing to the simplicity of their fabrication procedures and low cost. However, its low light-to-energy conversion efficiency and poor long-term reliability limit its large-scale ap-plication. TiO2 is the primary photoanode material; however, the surface state may confine electron mobility and cause recombination, which limits the in-crease in cell conversion efficiency.ZnO has been regarded as a promising candidate photoanode material with its similar band gaps as TiO2 and higher electronic mobility. Here a new nanobelt type ZnO photoanode was fabricated by electrodeposition and ap-plied to DSC. Using nanobelt structure ZnO can efficiently reduce resistance at the interfaces of crystal grains. The electrodeposition conditions affected the ZnO morphology and thus the performance of DSC remarkly. The effi-ciency of DSC increased with decreasing surfactant concentration or increas-ing electrodeposition potential or temperature. The influencing factors of ZnO-based solar cells such as film thickness and ZnO film morphology were also investigated.On the other hand, as the generation of Zn2+/dye aggregates will limit the increase of ZnO-based solar cells efficiency, coating and quantum-dots were used to suppress the formation of Zn2+/dye aggregates. As the coating method for TiO2 photoanode will cause the formation of acid, it was not suitable for coating ZnO photoanode. Here quantum-dots were used to replace dye and efficiency comparing favorably with sensitized with dye was obtained, which indicated that quantum-dots were efficient sensitizer for the ZnO photoanode.