Fabrication and photovoltaic performance of niobium doped TiO2 hierarchical microspheres with exposed {001} facets and high specific surface area

作者：Liu, Yongqiang; Ran, Huili; Fan, Jiajie^*; Zhang, Xiaoli; Mao, Jing; Shao, Guosheng

来源：Applied Surface Science, 2017, 410: 241-248.

DOI：10.1016/j.apsusc.2017.03.085

• Niobium doped TiO2
• Hierarchical microspheres {001} facetes
• Specific surface area
• Dye-sensitized solar cells (DSSCs)

The niobium doped hierarchical anatase TiO2 microspheres, which are consist of a serried nano-thorns and plicate nano-ribbons with exposed {001} facets, were synthesized using hydrothermal method followed by heat treatment. The effects of niobium on the microstructures and photovoltaic performances of the dye-sensitized solar cells (DSSCs) were studied. The results revealed that Nb5+ doping replaces Ti4+ cations in TiO2 lattice, and the bandgap of the films varies with increasing Nb doping concentration because of the downshift of the conduction band minimum (CBM). The niobium-doped TiO2 DSSCs with moderate loadings show enhanced performance comparing with their pure TiO2 counterparts. Optimally, the conversion efficiency of the Nb-3.5 (Nb 3.5 mol%) DSSC is 4.99%. This is higher than that (4.39%) of pure TiO2 cells by 13.7%. This is due to the fact that the Nb-doped solar cells have increased the number of the photo-induced electrons because of their exposed (001) facets and higher specific surface area; and enhanced electrons collection and transport because of the downshifted CBM of the Nb-doped TiO2. However, heavy Nb doping results in the decrease of the performance of the niobium-doped cells due to the excessive defects within the Nb-TiO2 samples resulting in enhanced charge recombination at defects.

• 出版日期2017-7-15
• 单位郑州大学