†Physical Chemistry, Centre of Molecular Devices, Department of Chemistry-Ångström Laboratory, Uppsala University, SE-75120 Uppsala, Sweden.
‡Laboratory of Photomolecular Science, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, EPFL-FSB-ISIC-LSPM, Station 6, CH-1015 Lausanne, Switzerland.
Anal Chem. 2015 Apr 7;87(7):3942-8. doi: 10.1021/ac504851f. Epub 2015 Mar 20.
Solid-state dye-sensitized solar cells (sDSCs) are devoid of such issues as electrolyte evaporation or leakage and electrode corrosion, which are typical for traditional liquid electrolyte-based DSCs. Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most popular and efficient p-type conducting polymers that are used in sDSCs as a solid-state hole-transporting material. The most convenient way to deposit this insoluble polymer into the dye-sensitized mesoporous working electrode is in situ photoelectrochemical polymerization. Apparently, the structure and the physicochemical properties of the generated conducting polymer, which determine the photovoltaic performance of the corresponding solar cell, can be significantly affected by the preparation conditions. Therefore, a simple and fast analytical method that can reveal information on polymer chain length, possible chemical modifications, and impurities is strongly required for the rapid development of efficient solar energy-converting devices. In this contribution, we applied matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for the analysis of PEDOT directly on sDSCs. It was found that the PEDOT generated in aqueous micellar medium possesses relatively shorter polymeric chains than the PEDOT deposited from an organic medium. Furthermore, the micellar electrolyte promotes a transformation of one of the thiophene terminal units to thiophenone. The introduction of a carbonyl group into the PEDOT molecule impedes the growth of the polymer chain and reduces the conductivity of the final polymer film. Both the simplicity of sample preparation (only application of the organic matrix onto the solar cell is needed) and the rapidity of analysis hold the promise of making MALDI MS an essential tool for the physicochemical characterization of conducting polymer-based sDSCs.
固态染料敏化太阳能电池（sDSCs）不存在电解质蒸发或泄漏以及电极腐蚀等问题，这些问题是传统基于液态电解质的 DSCs 的典型问题。聚（3,4-亚乙基二氧噻吩）（PEDOT）是最受欢迎和高效的 p 型导电聚合物之一，用于 sDSCs 作为固态空穴传输材料。将这种不溶性聚合物沉积到染料敏化介孔工作电极中的最方便的方法是原位光电化学聚合。显然，生成的导电聚合物的结构和物理化学性质会显著影响相应太阳能电池的光伏性能，而这些性质可以通过制备条件来影响。因此，对于高效太阳能转换器件的快速发展，强烈需要一种简单快速的分析方法，该方法能够揭示聚合物链长、可能的化学修饰和杂质的信息。在本研究中，我们将基质辅助激光解吸/电离质谱（MALDI MS）应用于 sDSCs 上的 PEDOT 分析。结果发现，在水胶束介质中生成的 PEDOT 具有比从有机介质中沉积的 PEDOT 相对较短的聚合物链。此外，胶束电解质促进噻吩端基单元之一转化为噻吩酮。聚合物分子中羰基的引入阻碍了聚合物链的生长并降低了最终聚合物膜的电导率。样品制备的简单性（仅需要将有机基质施加到太阳能电池上）和分析的快速性使其有望使 MALDI MS 成为基于导电聚合物的 sDSCs 的物理化学特性表征的重要工具。
