Aaronson Barak D B, Byers Joshua C, Colburn Alex W, McKelvey Kim, Unwin Patrick R
Department of Chemistry, University of Warwick, Gibbet Hill Rd, Coventry, CV4 7AL United Kingdom.
Anal Chem. 2015 Apr 21;87(8):4129-33. doi: 10.1021/acs.analchem.5b00288. Epub 2015 Apr 6.
The development of techniques for nanoscale structure-activity correlations is of major importance for the fundamental understanding and rational design of (photo)electrocatalysts. However, the low conversion efficiency of characteristic materials generates tiny photoelectrochemical currents at the submicrometer to nanoscale, in the fA range, which are challenging to detect and measure accurately. Here, we report the coupling of scanning electrochemical cell microscopy (SECCM) with photoillumination, to create a submicrometer spatial resolution cell that opens up high resolution structure-(photo)activity measurements. We demonstrate the capabilities of the technique as a tool for: (i) high spatial resolution (photo)activity mapping using an ionic liquid electrolyte at a thin film of TiO2 aggregates, commonly used as a photoanode in dye sensitized solar cells (DSSCs) and (ii) in situ (photo)activity measurements of an electropolymerized conjugated polymer on a transparent Au substrate in a controlled atmospheric environment. Quantitative data, including localized (photo)electrochemical transients and external quantum efficiency (EQE), are extracted, and prospects for further technique development and enhancement are outlined.
纳米级结构-活性相关性技术的发展对于（光）电催化剂的基本理解和合理设计至关重要。然而，特征材料的低转换效率在亚微米到纳米尺度上产生微小的光电化学电流，处于飞安范围内，准确检测和测量具有挑战性。在此，我们报告了扫描电化学池显微镜（SECCM）与光照射的耦合，以创建一个亚微米空间分辨率的电池，从而实现高分辨率结构-（光）活性测量。我们展示了该技术作为一种工具的能力：（i）在通常用作染料敏化太阳能电池（DSSC）光阳极的TiO2聚集体薄膜上，使用离子液体电解质进行高空间分辨率（光）活性映射；（ii）在可控大气环境中，对透明金基底上的电聚合共轭聚合物进行原位（光）活性测量。提取了包括局部（光）电化学瞬变和外量子效率（EQE）在内的定量数据，并概述了进一步技术发展和改进的前景。
