Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Korea.
ACS Nano. 2013 Feb 26;7(2):1027-35. doi: 10.1021/nn305341x. Epub 2013 Jan 15.
Ternary oxides are potential candidates as an electron-transporting material that can replace TiO₂ in dye-sensitized solar cells (DSSCs), as their electronic/optical properties can be easily controlled by manipulating the composition and/or by doping. Here, we report a new highly efficient DSSC using perovskite BaSnO₃ (BSO) nanoparticles. In addition, the effects of a TiCl₄ treatment on the physical, chemical, and photovoltaic properties of the BSO-based DSSCs are investigated. The TiCl₄ treatment was found to form an ultrathin TiO₂ layer on the BSO surface, the thickness of which increases with the treatment time. The formation of the TiO₂ shell layer improved the charge-collection efficiency by enhancing the charge transport and suppressing the charge recombination. It was also found that the TiCl₄ treatment significantly reduces the amount of surface OH species, resulting in reduced dye adsorption and reduced light-harvesting efficiency. The trade-off effect between the charge-collection and light-harvesting efficiencies resulted in the highest quantum efficiency (i.e., short-circuit photocurrent density), leading to the highest conversion efficiency of 5.5% after a TiCl₄ treatment of 3 min (cf. 4.5% for bare BSO). The conversion efficiency could be increased further to 6.2% by increasing the thickness of the BSO film, which is one of the highest efficiencies from non-TiO₂-based DSSCs.
三元氧化物是一种有前途的电子传输材料，可替代染料敏化太阳能电池（DSSC）中的 TiO₂，因为其电子/光学性质可以通过操纵组成和/或掺杂来轻松控制。在这里，我们报告了一种使用钙钛矿 BaSnO₃（BSO）纳米粒子的新型高效 DSSC。此外，还研究了 TiCl₄ 处理对基于 BSO 的 DSSC 的物理、化学和光伏性能的影响。研究发现，TiCl₄ 处理会在 BSO 表面形成一层超薄的 TiO₂ 层，其厚度随处理时间的增加而增加。TiO₂ 壳层的形成通过增强电荷输运和抑制电荷复合，提高了电荷收集效率。还发现，TiCl₄ 处理会显著减少表面 OH 物种的数量，从而减少染料吸附和光捕获效率。电荷收集和光捕获效率之间的权衡效应导致量子效率（即短路光电流密度）最高，经过 3 分钟 TiCl₄ 处理后，转换效率达到 5.5%（相比之下，裸 BSO 为 4.5%）。通过增加 BSO 薄膜的厚度，可以进一步提高转换效率，达到 6.2%，这是基于非 TiO₂ 的 DSSC 中的最高效率之一。
