Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.
Phys Chem Chem Phys. 2011 Aug 7;13(29):13196-201. doi: 10.1039/c1cp20540d. Epub 2011 Jun 28.
Charge separation in excited states upon visible light absorption is a central process in photovoltaic solar cell applications. Employing state-of-the-art first principles calculations based on time-dependent density functional theory (TDDFT), we simulate electron-hole dynamics in real time and illustrate the microscopic mechanism of charge separation at the interface between organic dye molecules and oxide semiconductor surfaces in dye-sensitized solar cells. We found that electron-hole separation proceeds non-adiabatically on an ultrafast timescale <100 fs at an anthocyanin/TiO(2) interface, and it is strongly mediated by the vibrations of interface Ti-O bonds, which anchor the dye onto the TiO(2) surface. The obtained absorption spectrum and electron injection timescale agree with experimental measurements.
在可见光吸收时，激发态中的电荷分离是光伏太阳能电池应用中的一个核心过程。我们采用基于含时密度泛函理论（TDDFT）的最先进的第一性原理计算，实时模拟电子-空穴动力学，并在染料敏化太阳能电池中阐明了有机染料分子与氧化物半导体表面之间界面处电荷分离的微观机制。我们发现，电子-空穴分离在超快时间尺度<100 fs 下非绝热进行，并且强烈受到界面 Ti-O 键振动的影响，这些振动将染料固定在 TiO2 表面上。得到的吸收光谱和电子注入时间尺度与实验测量相符。
