Abstract

Self-assembled monolayers (SAMs) have many applications such as the solar cells and water-spitting systems, which mimic the photosynthetic process in the plants and serve as an effective alternative to provide clean energy from the sun. Dye molecules that are self-assembled on semiconductor substrates (usually TiO₂) play essential roles in the photon-to-electron conversion process. However, many structural aspects and structure-properties of dyes in SAMs remain elusive, and the conformer structures of dye molecules and their effects on the properties of SAMs are frequently neglected. In fact, dye molecules can adopt multiple conformer structures on the TiO₂ substrate due to the existence of flexible alkyl chains and non-rigid backbones, which might affect the structures and properties of the dye-sensitized systems. In this research, we investigate the structures and effects of different conformers via the first principles calculations, employing an organic azo dye 4-[2-[4-(diethyl-amino)phenyl]diazenyl]-benzoic acid, which combines good transparency, aesthetic quality and electricity-generation properties. We find that various conformers of the organic dye could reside stably on the TiO₂ substrate, and the conformer effects are especially dominant when the dye aggregation model is considered. The relationship between the azo dye conformation and the azo dye aggregation is explained. Our calculations demonstrate that including the conformer effects leads to diverse structures and properties of the azo dye/TiO₂ systems, which could be important for the devices containing the dye/TiO₂ systems such as the dye-sensitized solar cells, smart windows and dye-sensitized water splitting systems.

中文翻译：

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从头开始研究染料共形物结构以及TiO 2上构象与多层聚集体在太阳能电池应用中的相互作用

摘要

自组装单分子膜（SAMs）具有许多应用，例如太阳能电池和吐水系统，它们模仿植物中的光合作用过程，并且是从太阳提供清洁能源的有效替代方法。自组装在半导体衬底上的染料分子（通常为TiO ₂）在光子-电子转换过程中起着至关重要的作用。然而，SAM中染料的许多结构方面和结构性质仍然难以捉摸，并且染料分子的构象结构及其对SAMs性质的影响经常被忽略。实际上，染料分子可以在TiO ₂上采用多种构象结构由于存在柔性烷基链和非刚性主链，因此可能会影响染料敏化系统的结构和性能。在这项研究中，我们通过使用有机偶氮染料4- [2- [4-（2-（二乙基-氨基）苯基]重氮基]-苯甲酸，结合了良好的透明度，通过第一个原理计算来研究不同构象异构体的结构和作用，美学品质和发电特性。我们发现有机染料的各种构象异构体可以稳定地存在于TiO _2上当考虑染料聚集模型时，构象效应尤其显着。说明了偶氮染料的构象与偶氮染料的聚集之间的关系。我们的计算表明，包括构象效应会导致偶氮染料/ TiO ₂系统的结构和性能多样化，这对于包含染料/ TiO ₂系统的设备（如染料敏化太阳能电池，智能窗户和染料）可能非常重要敏化的水分解系统。