School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, QLD 4001, Australia.
Beilstein J Nanotechnol. 2012;3:378-87. doi: 10.3762/bjnano.3.44. Epub 2012 May 7.
An anatase TiO(2) material with hierarchically structured spheres consisting of ultrathin nanosheets with 100% of the [001] facet exposed was employed to fabricate dye-sensitized solar cells (DSCs). Investigation of the electron transport and back reaction of the DSCs by electrochemical impedance spectroscopy showed that the spheres had a threefold lower electron recombination rate compared to the conventional TiO(2) nanoparticles. In contrast, the effective electron diffusion coefficient, D(n), was not sensitive to the variation of the TiO(2) morphology. The TiO(2) spheres showed the same D(n) as that of the nanoparticles. The influence of TiCl(4) post-treatment on the conduction band of the TiO(2) spheres and on the kinetics of electron transport and back reactions was also investigated. It was found that the TiCl(4) post-treatment caused a downward shift of the TiO(2) conduction band edge by 30 meV. Meanwhile, a fourfold increase of the effective electron lifetime of the DSC was also observed after TiCl(4) treatment. The synergistic effect of the variation of the TiO(2) conduction band and the electron recombination determined the open-circuit voltage of the DSC.
采用具有由暴露了 100%[001]晶面的超薄纳米片组成的分级结构球体的锐钛矿 TiO(2) 材料来制备染料敏化太阳能电池 (DSC)。通过电化学阻抗谱研究 DSC 的电子输运和反向反应，发现与传统的 TiO(2) 纳米颗粒相比，球体的电子复合率降低了三倍。相比之下，有效电子扩散系数 D(n) 对 TiO(2) 形态的变化不敏感。TiO(2)球体显示出与纳米颗粒相同的 D(n)。还研究了 TiCl(4)后处理对 TiO(2)球体导带和电子输运及反向反应动力学的影响。结果发现，TiCl(4)后处理使 TiO(2)导带边缘向下移动了 30 meV。同时，在 TiCl(4)处理后，DSC 的有效电子寿命也增加了四倍。TiO(2)导带的变化和电子复合的协同作用决定了 DSC 的开路电压。
