Polymers for Solar Energy Applications: Exploring Charge Carriers with Raman Spectroscopy and Electrochemistry

半导体聚合物在有机光致发光、光致发光和其它能源应用中是重要的。有机光伏器件的稳定性是限制其商业化的关键因素，但主要降解机制的结构起源在很大程度上仍然未知。该项目将确定带电聚合物（光伏运行期间的活性物质）中发生的特定结构变化，以及已知的降解因素，如氧气和水。反过来，这将有助于设计新的、更坚固的材料。识别特定的降解机制不仅有利于有机光伏领域，而且有利于使用此类聚合物的许多其他应用：例如显示技术中的发光二极管。为了探索半导体聚合物中的这些降解机制，将电化学和拉曼光谱相结合，以创建强大的，但很少使用的光谱电化学共振拉曼。该技术不仅对分子结构和构象的微小变化高度敏感，而且还允许在多个共存物种的系统中选择性地探测单个物种。因此，本项目的目的是应用光谱电化学共振拉曼这一新技术的一系列共轭聚合物，以确定特定的结构变化，在电子转移过程中，以阐明其降解机制。该项目的一个直接成果将是创建设计规则，以减轻有机光伏材料的退化。因此，该项目直接与EPSRC的能源主题保持一致，解决能源应用材料，化学结构和电化学科学的研究领域。

Semiconducting polymers are important in organic photovoltaics, photocatalysis, and other energy applications. The stability of organic photovoltaic devices is a critical factor limiting their commercialisation, but structural origins of the primary degradation mechanisms remain largely unknown. This project will identify specific structural changes that occur in the charged polymers (the active species during photovoltaic operation) in combination with known degradation factors such as oxygen and water. In turn, this will enable the design of new, more robust materials. Identification of specific degradation mechanisms will benefit not just the organic photovoltaic field, but also many other applications where such polymers are utilised: light emitting diodes in display technology, for example. To explore these degradation mechanisms in semiconducting polymers, electrochemistry and Raman spectroscopy will be combined to create the powerful but seldom-used spectroelectrochemical resonance Raman. This technique is not only highly sensitive to small changes in molecular structure and conformation, but also allows the selective probing of a single species in a system with multiple co-existing species. This project therefore aims to apply this novel technique of spectroelectrochemical resonance Raman to a series of conjugated polymers to ascertain specific structural changes during electron transfer, in order to elucidate their degradation mechanisms. A direct outcome of this project will be the creation of design rules to alleviate degradation in organic photovoltaic materials. As such, this project aligns directly with EPSRC's Energy theme, tackling the research areas of Materials for Energy Applications, Chemical Structure, and Electrochemical Sciences.