Wang Qing, Moser Jacques-E, Grätzel Michael
Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
J Phys Chem B. 2005 Aug 11;109(31):14945-53. doi: 10.1021/jp052768h.
Electrochemical impedance spectroscopy (EIS) has been performed to investigate electronic and ionic processes in dye-sensitized solar cells (DSC). A theoretical model has been elaborated, to interpret the frequency response of the device. The high-frequency feature is attributed to the charge transfer at the counter electrode while the response in the intermediate-frequency region is associated with the electron transport in the mesoscopic TiO2 film and the back reaction at the TiO2/electrolyte interface. The low-frequency region reflects the diffusion in the electrolyte. Using an appropriate equivalent circuit, the electron transport rate and electron lifetime in the mesoscopic film have been derived, which agree with the values derived from transient photocurrent and photovoltage measurements. The EIS measurements show that DSC performance variations under prolonged thermal aging result mainly from the decrease in the lifetime of the conduction band electron in the TiO2 film.
已采用电化学阻抗谱（EIS）来研究染料敏化太阳能电池（DSC）中的电子和离子过程。已构建了一个理论模型来解释该器件的频率响应。高频特性归因于对电极处的电荷转移，而中频区域的响应与介观TiO₂薄膜中的电子传输以及TiO₂/电解质界面处的背反应有关。低频区域反映了电解质中的扩散。通过使用合适的等效电路，得出了介观薄膜中的电子传输速率和电子寿命，这些值与通过瞬态光电流和光电压测量得出的值一致。EIS测量表明，长时间热老化下DSC性能的变化主要源于TiO₂薄膜中导带电子寿命的降低。
