Drift Transport in Al2O3-Sheathed 3-D Transparent Conducting Oxide Photoanodes Observed in Liquid Electrolyte-Based Dye-Sensitized Solar Cells

作者：Liu Fa Qian; Zhu Kai^*; Li Tao; Xu Tao

来源：Journal of Physical Chemistry C, 2014, 118(19): 9951-9957.

DOI：10.1021/jp502220m

It has long been taken for granted that electron transport in liquid-electrolyte-based dye-sensitized solar cells (DSSCs) undergoes an ambipolar diffusive transport due to the strong coupling between electrons in the photoanode and the nearby mobile cations in liquid electrolyte, which, therefore, screens off any electric field in the photoanodes and consequently eliminates the possibility for drift transport. In this work, we demonstrate the existence of drift transport in liquid electrolyte-based DSSCs using a thin Al2O3-sheathed 3-dimentional (3-D) fluorinated tin oxide (FTO), as photoanodes. The electron diffusion rate in such 3-D TCO based DSSC exhibits a striking enhancement to the value of similar to 10(-2) cm(2)/s, about 10(4) times faster than that of the TiO2 nanoparticle-based DSSCs. The electron diffusion coefficient is independent of the photoelectron density, while intensity modulated photocurrent spectroscopy (IMPS) suggests that the time constants of electron transport exhibit a linear dependence on the bias voltage, a strong indication of drift transport behavior in this 3-D FTO hollow nanobeads-based DSSC, despite the use of liquid I-/I-3(-) electrolyte.

• 出版日期2014-5-15