NSERC-DFG SUSTAIN - Enhanced solar-energy capture through optimization of up- and down-conversion in organic molecules

该提案概述了一项跨学科计划，旨在通过合成富含碳的分子和材料来扩大太阳能捕获和转换的边界。经过战略性设计的有机分子将被用来克服当前用于将光转化为电能的过程所固有的热力学限制。具体地说，分子设计可以用来回答关于两个过程的基本和应用问题，单态裂变(SF)和三重态湮没上转换(TTA-UC)。有机材料中这两种工艺的结合为下一代利用太阳能的设备提供了提高效率的潜力。我们认为，苯的逐步取代将允许结合能够提供稳定性、溶解性和功能的基团(烯=以苯环的线性融合序列为特征的分子)。对并苯结构的精确控制将有助于通过SF和TTA-UC进行太阳能转换。然后，仔细的分子设计与世界领先的理论和光物理表征相结合，以了解、优化和实施太阳能电池中的有机分子。光物理分析将通过飞秒、微微、纳米和微秒分辨实验提供对SF和TTA-UC的详细机制理解。换句话说，我们使用光谱学在快到千分之一秒的时间范围内“观察”分子。为了理解SF和TTA-UC的基本方面，我们将依靠复杂的理论和计算方法。这些模拟提供了这些超快过程的理论推导模型，在分子吸收光后通过光谱观察到这些过程。结合实验测量，开发了一幅完整的图景，既可以理解个别类别的分子，也可以计划将其实施到太阳能转换计划中。

This proposal outlines an interdisciplinary plan to expand the boundaries of solar-energy capture and conversion through the synthesis of carbon-rich molecules and materials. Strategically designed organic molecules will be used to overcome the thermodynamic limitations inherent to the current generation of processes used to convert light into electricity. Specifically, molecular design can be used to answer both fundamental and applied questions regarding two processes, singlet fission (SF) and triple-triplet annihilation upconversion (TTA-UC). The combination of these two processes in organic materials offers the potential for improved efficiency in the next generation of devices to harness solar energy. We propose that the stepwise substitution of acenes will allow incorporation of groups that can provide stability, solubility, and function (acenes = molecules featuring a linearly fused sequence of benzene rings). Precise control of the structure of acenes will facilitate solar-energy conversion through SF and TTA-UC. Careful molecular design is then combined with world-leading theoretical and photophysical characterization to understand, optimize, and implement organic molecules in solar cells. Photophysical analyses will provide a detailed mechanistic understanding of SF and TTA-UC through femto-, pico-, nano-, and micro-second-resolved experiments. In other words, we use spectroscopy to "watch" molecules over time frames as fast as one quadrillionth of a second to as slow as one thousandth of a second. To understand fundamental aspects of SF and TTA-UC, we will rely on complex theoretical and computational methods. These simulations provide theoretically derived models of these ultrafast processes that are spectroscopically observed after the molecules absorb light. Coupled with experimental measurements, a wholistic picture is developed both to understand individual classes of molecules as well as plan for their implementation into solar conversion schemes.