通过氧气空位控制荷载体的捕获和放松 荷载: Ab Initio 非adiabatic 分子动力学
Zhaohui Zhou1,2, Jin Liu2, Run Long3
1International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University , Xi'an 710049, China.
Journal of the American Chemical Society
|April 27, 2017
概括
在血 (α-Fe2O3) 中超快速的电荷重组阻碍了太阳能应用. 氧气空隙 (Ov) 影响重组动力学,有离子化的Ov缺陷可提高电荷载体寿命,从而提高光电极性能.
科学领域:
- 材料科学
- 计算化学
- 可再生能源
背景情况:
- 血 (α-Fe2O3) 中的超快速电荷重组限制了其在光电化学水分裂等太阳能转换技术中的效率.
- 了解电荷载体动力学,特别是电子孔重组,对于优化基于血的光电极至关重要.
研究的目的:
- 调查血 (α-Fe2O3) 具有和没有氧空位 (Ov) 缺陷的时间域电荷放松动态.
- 阐明电子孔重组的机制以及Ov缺陷对这些过程的影响.
主要方法:
- 在时间依赖密度函数理论中使用非adiabatic分子动态的时间域ab initio模拟.
- 在原始和含有Ov的血晶格中研究了电荷放松动态.
主要成果:
- 在中性和电离的Ov系统中,洞捕获被确定为电子洞重组的速度限制步骤.
- 中性Ov缺陷显著加快重组 (大约 30倍),而电离化的Ov缺陷则会降低它 (约. 与中性Ov相比,提高了导电性和载体寿命.
- 模拟准确地复制了热载体冷却,捕获和重组的实验时间表.
结论:
- 在血中氧气空位的离子化对于改善光电极的电导率和电荷载体寿命至关重要.
- 这项研究提供了对血载体动态的原子化见解,解释了 Ov 修饰的光电极的性能提升.
- 确定了Ov辅助电子孔重组的两个潜在机制.
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