Influence of thermal fluctuations on interfacial electron transfer in functionalized TiO2 semiconductors
Influence of thermal fluctuations on interfacial electron transfer in functionalized TiO2 semiconductors
复制标题
DOI：
10.1021/ja055185u
复制
发表时间：
2005-12-28
影响因子：
15
通讯作者：
Batista, VS
中科院分区：
文献类型：
--
作者：
Abuabara, SG;Rego, LGC;Batista, VS
采用从头算密度泛函分子动力学模拟和瞬时电子激发的量子动力学传播相结合的方法，研究了热涨落对敏化锐钛矿型二氧化钛半导体界面电子转移动力学的影响。结果表明，热核涨落通过在电子受主态间引入非绝热跃迁来加速界面电子转移动力学，电子受主态局域化在光激发吸附态附近，离域态扩展到整个半导体材料，为载流子扩散创造了额外的弛豫路径。此外，研究还表明，室温热涨落降低了锐钛矿型晶体中电荷沿不同方向扩散的各向异性，使不同性质的吸附态的电子注入速率相近。所报道的结果与理解温度对分子基光器件中表面电荷分离机制的影响特别相关。
The influence of thermal fluctuations on the dynamics of interfacial electron transfer in sensitized TiO2-anatase semiconductors is investigated by combining ab initio DFT molecular dynamics simulations and quantum dynamics propagation of transient electronic excitations. It is shown that thermal nuclear fluctuations speed up the underlying interfacial electron transfer dynamics by introducing nonadiabatic transitions between electron acceptor states, localized in the vicinity of the photoexcited adsorbate, and delocalized states extended throughout the semiconductor material, creating additional relaxation pathways for carrier diffusion. Furthermore, it is shown that room-temperature thermal fluctuations reduce the anisotropic character of charge diffusion along different directions in the anatase crystal and make similar the rates for electron injection from adsorbate states of different character. The reported results are particularly relevant to the understanding of temperature effects on surface charge separation mechanisms in molecular-based photo-optic devices.