Department of Chemistry, Columbia University, New York, New York 10027, USA.
J Am Chem Soc. 2012 Jul 25;134(29):12028-42. doi: 10.1021/ja3013787. Epub 2012 Jul 16.
We have developed a cluster model of a TiO(2) nanoparticle in the dye-sensitized solar cell and used first-principles quantum chemistry, coupled with a continuum solvation model, to compute structures and energetics of key electronic and structural intermediates and transition states. Our results suggest the existence of shallow surface trapping states induced by small cations and continuum solvent effect as well as the possibility of the existence of a surface band which is 0.3-0.5 eV below the conduction band edge. The results are in uniformly good agreement with experiment and establish the plausibility of an ambipolar model of electron diffusion in which small cations, such as Li(+), diffuse alongside the current carrying electrons in the device, stabilizing shallowing trapping states, facilitating diffusion from one of these states to another, in a fashion that is essential to the functioning of the cell.
我们已经开发了一个染料敏化太阳能电池中 TiO(2)纳米粒子的团簇模型，并使用第一性原理量子化学，结合连续溶剂化模型，计算了关键电子和结构中间体以及过渡态的结构和能量。我们的结果表明，小阳离子和连续溶剂效应会导致表面陷阱态变浅，并且可能存在表面能带，其低于导带边缘 0.3-0.5eV。这些结果与实验结果一致，证明了电子扩散的双极模型的合理性，在该模型中，Li(+)等小阳离子与器件中的载流电子一起扩散，稳定浅的陷阱态，促进从一个态到另一个态的扩散，这对电池的运行至关重要。
