Symmetry-Breaking Charge Separation Materials for Single-junction Organic Photovoltaics

对称破缺电荷分离（SB-CS）是光合作用反应中心初级电荷分离过程的关键步骤之一，结构或环境波动打破了发色团对的激发态对称性，产生电荷分离（CS）状态。有机光伏（OPVs）在室内光收集、建筑和车辆集成光伏应用中越来越受到关注。与传统的无机光伏不同，OPV器件通常使用有机供体和受体分子的组合来解离激子并产生光电流。在过去的几年里，opv的性能有了快速的进步，单结opv的功率转换效率已经达到了19%以上。该过程涉及固态的分子间相互作用，而不像SB-CS材料涉及分子内相互作用。然而，这提出了一个有趣的问题，如果SB-CS材料可以在固态下设计，以利用分子内和分子间的效应呢？这是否可以在低介电固体环境中产生长寿命的电荷？该项目将探索基于SB-CS材料的单结opv这一尚未被探索的领域。据报道，SB-CS材料通过分子内相互作用产生短寿命的CS态。本课题旨在利用分子间相互作用，创新一种有效的电荷转移模型，提高固态SB-CS材料的CS寿命。发色团的刚性正交或近正交排列被认为是一种优雅的设计，可以实现有效的电荷分离。分子功能化和材料的结构和光物理特性将被执行，以解决科学挑战。制作单室OPV装置，项目的建成将为单结OPV进一步系统改进开辟道路。

Symmetry-breaking charge separation (SB-CS) is one of the key steps in the primary charge separation process of the photosynthesis reaction center, where structural or environmental fluctuations break the excited state symmetry of the chromophoric pair and yield a charge-separated (CS) state. Organic photovoltaics (OPVs) are of growing interest for indoor light harvesting, building, and vehicle-integrated photovoltaics applications. Unlike conventional inorganic photovoltaics, OPV devices conventionally use a combination oforganic donor and acceptor molecules to dissociate excitons and generate photocurrent. There have been rapid advances in the performance of OPVs in the past few years, and single-junction OPVs have achieved a power conversion efficiency above 19%. This process involves intermolecular interactions in the solid state, unlike the SB-CS materials, which involve intramolecular interaction. However, this raises a fascinating question, what if SB-CS materials could be engineered in the solid state to take advantage of both intramolecular and intermolecular effects? Could this allow long-lived charge generation in low-dielectric solid-state environments? This project will venture into this less-explored area of SB-CS material-based single-junction OPVs. SB-CS materials are reported to generate a short-lived CS state via intramolecular interaction. This proposal aims to enhance the CS lifetime of SB-CS material in the solid state by exploiting intermolecular interactions to innovate an efficient charge transfer model. The rigid orthogonal or near-orthogonal arrangement of chromophores is considered an elegant design that renders efficient charge separation. Molecular functionalization and structural and photophysical characterization of materials will be performed to address the scientific challenge. A single-compartment OPV device will be made, and the project's completion will unleash paths for further systematic improvement of single-junction OPVs.