Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
J Am Chem Soc. 2011 May 25;133(20):7816-23. doi: 10.1021/ja200001r. Epub 2011 May 4.
Anatase TiO(2) is a widely used photocatalytic material, and catechol (1,2-benzendiol) is a model organic sensitizer for dye-sensitized solar cells. The growth and the organization of a catecholate monolayer on the anatase (101) surface were investigated with scanning tunneling microscopy and density functional theory calculations. Isolated molecules adsorb preferentially at steps. On anatase terraces, monodentate ('D1') and bidentate ('D2') conformations are both present in the dilute limit, and frequent interconversions can take place between these two species. A D1 catechol is mobile at room temperature and can explore the most favorable surface adsorption sites, whereas D2 is essentially immobile. When a D1 molecule arrives in proximity of another adsorbed catechol in an adjacent row, it is energetically convenient for them to pair up in nearest-neighbor positions taking a D2-D2 or D2-D1 configuration. This intermolecular interaction, which is largely substrate mediated, causes the formation of one-dimensional catecholate islands that can change in shape but are stable to break-up. The change between D1 and D2 conformations drives both the dynamics and the energetics of this model system and is possibly of importance in the functionalization of dye-sensitized solar cells.
锐钛矿 TiO(2) 是一种广泛应用的光催化材料，儿茶酚（1,2-苯二酚）是染料敏化太阳能电池的一种模型有机敏化剂。本研究使用扫描隧道显微镜和密度泛函理论计算，对儿茶酸盐在锐钛矿（101）表面的生长和组织进行了研究。孤立的分子优先在台阶处吸附。在锐钛矿平台上，在稀溶液条件下，单齿（'D1'）和双齿（'D2'）构象都存在，且这两种构象之间可以频繁转换。室温下，D1 儿茶酚是可移动的，它可以探索最有利的表面吸附位置，而 D2 则基本上是不可移动的。当一个 D1 分子在相邻行中接近另一个吸附的儿茶酚时，它们之间形成 D2-D2 或 D2-D1 构型的相邻对是能量有利的。这种主要由基底介导的分子间相互作用导致一维儿茶酸酯岛的形成，这种岛可以改变形状，但不会轻易断裂。D1 和 D2 构象的变化既驱动了该模型系统的动力学又驱动了其热力学，这可能对染料敏化太阳能电池的功能化具有重要意义。
