TiO2 nanotube array is a promising nanostructure for photoanode in the third generation solar cells such as dye-sensitized solar cells and semiconductor-sensitized solar cells. Electrodeposition is an important method to deposit semiconductor. But, when it is applied to nanostructures such as nanotube arrays with long nanochannels, the deposited material tends to clog at the open end of the pores and prevent material from further depositing into the inner parts. To solve this problem, we introduced a novel two step electrodeposition method to improve the inner space electrodeposition and successfully fabricated CdSe/TiO2nanotube structure.In a traditional electrodeposition process, during the deposition, the CdSe tends to clog at the opening of the nanotubes shown as Fig.1a. To further observe the inner morphologies, we have scratched the nanotube arrays with a blade to get a fault surface, Fig. 1b, from which no CdSe deposit can be found. While in our modified two-step electrodeposition process is taken by first applying a relative high potential for a short time, then change to a lower potential for a certain time period. By this method, the open ends of the nanotubes will not be blocked, shown in Fig. 1c and d, so that CdSe can be deposited into the inner parts of the nanotubes.   Fig. 1  SEM images of CdSe/TiO2 nanotube arrays fabricated by a traditional electrodeposition method (a), (b) and the novel electrodeposition method (c), (d).In summary, by the new electrodeposition method, CdSe can be deposited into the inner walls of nanostructures. Furthermore, this method can be also applied to other semiconductors like CdS, CdTe, PbS, etc, enabling layer by layer deposition of different materials into nanopores which is promising in fabricating heterojunction with well designed energy diagram for solar cells.

Novel electrodeposition fabrication method of CdSe/TiO<sub>2</sub> heterojunction nanostructure for solar cell

248th National Meeting (2014)

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Novel electrodeposition fabrication method of CdSe/TiO2 heterojunction nanostructure for solar cell

Novel electrodeposition fabrication method of CdSe/TiO₂ heterojunction nanostructure for solar cell