Photoinduced Formation of Polythiophene/TiO2 Nanohybrid Heterojunction Films for Solar Cell Applications
Photoinduced Formation of Polythiophene/TiO2 Nanohybrid Heterojunction Films for Solar Cell Applications
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DOI：
10.1021/jp7099064
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发表时间：
2008-03
期刊：
影响因子：
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通讯作者：
Y. Otsuka;Y. Okamoto;H. Y. Akiyama;K. Umekita;Y. Tachibana;S. Kuwabata
中科院分区：
文献类型：
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作者：
Y. Otsuka;Y. Okamoto;H. Y. Akiyama;K. Umekita;Y. Tachibana;S. Kuwabata
研究了利用 TiO2 纳米孔内噻吩的光诱导聚合形成纳米结构聚噻吩/TiO2 异质结薄膜。所得薄膜在 TiO2 纳米多孔域内具有纳米杂化和电子连接。光聚合分三个阶段进行：(i) 共价连接到 TiO2 表面的联噻吩的光激发，(ii) 从表面连接的噻吩到 TiO2 的电子注入反应，以及 (iii) 从电解质中的噻吩反应物到表面连接的联噻吩的电子转移。通过分析一系列实验，例如光照射时间、施加偏压、电解质类型、噻吩反应物类型及其形态，解释了最初的快速光聚合和随后的缓慢聚合物生长。 TiO2 上吸附的联噻吩的电化学测量揭示了氧化还原电位的广泛分布。这可以通过 TiO2 表面局部电场的影响以及表面结合的联噻吩和 TiO2 之间的强相互作用来解释。该纳米杂化薄膜应用于敏化型光电化学太阳能电池，证实了纳米杂化薄膜在电子器件中的直接应用。太阳能电池的性能与纳米杂化薄膜的界面结构和光聚合程度密切相关。
Formation of nanostructured polythiophene/TiO2 heterojunction films, using photoinduced polymerization of thiophene inside TiO2 nanopores, was investigated. The resultant film possesses nanohybridization and electronic connection within the TiO2 nanoporous domain. Photopolymerization proceeded in three stages: (i) photoexcitation of bithiophene covalently attached to the TiO2 surface, (ii) an electron injection reaction from the surface attached thiophene to the TiO2, and (iii) an electron transfer from a thiophene reactant in an electrolyte to the surface-attached bithiophene. Initial rapid photopolymerization and subsequent slow polymer growth were explained by analysis of a series of experiments, e.g., with respect to light irradiation time, applied bias, electrolyte types, thiophene reactant type, and their morphology. Electrochemical measurements for the bithiophene adsorbed on TiO2 revealed a wide distribution of redox potentials. This was explained by influence of the local electric field on the TiO2 surface in addition to strong interaction between the surfacebound bithiophene and the TiO2. The nanohybrid film was applied to a sensitized-type photoelectrochemical solar cell, substantiating direct application of the nanohybrid film to electronic devices. The solar cell performance was closely associated with the interfacial structure in the nanohybrid film and the photopolymerization degree.