Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China.
University of Chinese Academy of Sciences , Beijing 100049, China.
Langmuir. 2018 Jan 9;34(1):546-552. doi: 10.1021/acs.langmuir.7b02977. Epub 2017 Dec 28.
Dye-sensitized solar cells (DSSCs) have aroused intensive interest for the replacement of conventional crystalline silicon solar cells. Through carboxylic acid groups, the dyes attach to the TiO anatase (101) surface, on which the subsurface oxygen vacancies (Vos) are predominant. The performance of DSSCs can be affected by the presence and positions of oxygen vacancies (Vos). By applying density functional theory calculations, we found that the adsorption of a carboxylic acid group-decorated dye molecule reverses the relative stability between the surface oxygen vacancy (Vo) and Vo on the anatase (101) surface, which facilitates the migration of the Vo from the subsurface to the surface by overcoming an energy barrier of less than 0.16 eV, which is significantly lower than the 1.01 eV energy barrier on the clean surface. Further, ab initio molecular dynamics simulations indicate that the Vo can easily migrate to the surface at room temperature. This dynamic interplay between the Vo of the anatase (101) surface and the carboxylic acid group would be important for future studies concerning the stability and photovoltaic efficiency of the solar cells.
染料敏化太阳能电池 (DSSC) 已引起人们对替代传统晶体硅太阳能电池的浓厚兴趣。通过羧酸基团，染料附着在 TiO2 锐钛矿 (101) 表面，其中亚表面氧空位 (Vos) 占主导地位。DSSC 的性能可能会受到氧空位 (Vos) 的存在和位置的影响。通过应用密度泛函理论计算，我们发现，羧酸基团修饰的染料分子的吸附会逆转锐钛矿 (101) 表面氧空位 (Vo) 和 Vo 之间的相对稳定性，从而通过克服低于 0.16eV 的能量势垒，促使 Vo 从亚表面迁移到表面，这明显低于清洁表面上的 1.01eV 能量势垒。此外，从头分子动力学模拟表明，Vo 可以在室温下很容易地迁移到表面。这种锐钛矿 (101) 表面 Vo 和羧酸基团之间的动态相互作用对于未来研究太阳能电池的稳定性和光伏效率非常重要。
