Theory of the impedance of electron diffusion and recombination in a thin layer
Theory of the impedance of electron diffusion and recombination in a thin layer
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DOI：
10.1021/jp011941g
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发表时间：
2002-01-17
影响因子：
3.3
通讯作者：
Bisquert, J
中科院分区：
文献类型：
--
作者：
Bisquert, J
本文分析了空间受限情况下电子扩散和复合的小信号交流阻抗，并将其应用于多孔TiO2纳米结构光电极和本征聚合物等体系。结果表明，具有主要边界条件类型的扩散-复合模型在频域上假设了一组有限的可能行为，并根据相关的物理参数进行了分类。有四种可能的情况：(i)具有反射边界的有限扩散阻抗，（ii）具有吸收边界的有限扩散阻抗，（iii）半无限空间中的扩散-反应阻抗或Gerischer阻抗，以及（iv）高频Warburg响应和低频反应弧相结合的阻抗。从电化学电位或准费米能级的空间分布以及传输线表示的角度讨论了该方法的通用性。对锂插层电极内的扩散与均相固相反应进行了扩展。建立了与描述电化学系统中输运和反应的其他框架的联系。
This paper analyzes the small signal ac impedance of electron diffusion and recombination in a spatially restricted situation with application in systems such as porous TiO2 nanostructured photoelectrodes and intrinsically conducting polymers. It is shown that the diffusion-recombination model with the main types of boundary conditions assumes a finite set of possible behaviors in the frequency domain, which are classified according to relevant physical parameters. There are four possible cases: (i) the impedance of finite diffusion with reflecting boundary, (ii) the impedance of finite diffusion with absorbing boundary, (iii) the impedance of diffusion-reaction in semiinfinite space or Gerischer impedance, and (iv) the impedance that combines Warburg response at high frequency and a reaction arc at low frequency. The generality of the approach is discussed in terms of the spatial distribution of the electrochemical potential or quasi-Fermi level and also in terms of the transmission line representation. An extension is considered to the diffusion in lithium intercalation electrodes coupled to a homogeneous solid-state reaction. The connection is established with other frameworks for the description of transport and reaction in electrochemical systems.