Molecular mechanisms of energy storage and release in MOST systems

在化石燃料资源日益减少的时代，越来越需要有效的能源生产和储存。分子太阳能热（MOST）能量转换系统已成为存储太阳能的有吸引力的替代方案。这种转换通常发生在超快的时间尺度上。因此，超快激光光谱学是实时分析这些光诱导过程的理想选择。在这个项目中，最先进的时间分辨光学光谱技术将被用于研究新型的、合理设计的降冰片二烯（NBD）、氮杂氮素（BN）和偶氮苯（AB）基高分子材料的初级光化学。我们的研究将为这些高分子材料的主要光化学转化反应和不同取代基对热能储存效率的作用提供分子理解。我们还将开发照明方案，以优化热能释放（WP1）。混合MOST系统提供了增加存储能量密度和扩大光收集光谱范围的潜力。基于以往对多发色团化合物的研究，我们将研究连接模式对单个发色团单元的可寻址性和功能、分子间和分子内相互作用以及热稳定性（WP2）的影响。我们还将针对基于共价和非共价相互作用的多聚体的AB化合物的动力学。稳定系统可以通过π π堆叠或吸引伦敦色散力来实现，它们的目标是同时增加存储能量密度和稳定热能存储状态（WP3）。在实际应用中，大多数化合物需要在高密度环境中工作，在高密度环境中，分子间相互作用经常影响光化学性质。在MOST薄膜和特定表面上进行超快光谱实验，并与WP1的溶液实验结果进行比较，将指导联盟努力优化技术设备的总体性能（WP4）。在FOR MOST内，与合成组的密切合作将支持新的MOST化合物的设计和优化。与理论小组一起，我们将大大有助于开关和存储过程的机械方面的详细了解。

In times of diminishing fossil fuel resources, there is an increasing need for efficient energy generation and storage. Molecular solar thermal (MOST) energy conversion systems have become attractive alternatives to storing solar energy. This conversion typically occurs on an ultrafast time scale. Therefore, ultrafast laser spectroscopy is ideally suited to analyze these photoinduced processes in real time. Within this project, state-of-the-art time-resolved optical spectroscopic techniques will be employed to study the primary photochemistry of novel, rationally designed norbornadiene (NBD), azaborine (BN) and azobenzene (AB) based mostophores. Our studies will provide molecular understanding of the primary photochemical conversion reactions of these mostophores and the role of different substituents on thermal energy storage efficiency. We will also develop illumination protocols for optimized thermal energy release (WP1). Hybrid MOST systems offer the potential of an increased storage energy density and an expanded spectral range for light harvesting. Based on previous studies of multi-chromophoric compounds we will investigate the influence of connectivity patterns on the addressability and functionality of the individual chromophore units, inter- and intramolecular interactions and thermal stability (WP2). We will also target the dynamics of AB compounds based on covalently and non covalently interacting multimers. Stabilized systems can be achieved by e.g. π π stacking or by attractive London dispersion forces, they aim at simultaneously increasing the storage energy density and stabilizing the thermal energy storage state (WP3). For practical applications it is required that MOST compounds operate in high-density environment, where intermolecular interactions often affect the photochemical properties. Ultrafast spectroscopic experiments on MOST films and on defined surfaces and comparison to the results of the solution experiments from WP1 will guide the consortium efforts towards optimizing the general performance of technological devices (WP4). Within FOR MOST the close collaboration with the synthetic groups will support the design and optimization of new MOST compounds. Together with the theory groups we will substantially contribute to a detailed understanding of mechanistic aspects of switching and storage processes.