Mony Jürgen, Yu Yi, Schäfer Clara, Mallick Suman, Kushwaha Khushbu, Börjesson Karl
Department of Chemistry and Molecular Biology, University of Gothenburg, Kemigården 4, Gothenburg 41296, Sweden.
J Phys Chem C Nanomater Interfaces. 2022 May 12;126(18):7965-7972. doi: 10.1021/acs.jpcc.2c01239. Epub 2022 May 3.
Strong exciton-photon coupling exhibits the possibility to modify the photophysical properties of organic molecules. This is due to the introduction of hybrid light-matter states, called polaritons, which have unique physical and optical properties. Those strongly coupled systems provide altered excited-state dynamics in comparison to the bare molecule case. In this study, we investigate the interplay between polaritonic and molecular trap states, such as excimers. The molecules used in this study show either prompt or delayed emission from trap states. For both cases, a clear dependency on the exciton-photon energy tuning was observed. Polaritonic emission gradually increased with a concurrent removal of aggregation-induced emission when the systems were tuned toward lower energies. For prompt emission, it is not clear whether the experimental results are best explained by a predominant relaxation toward the lower polariton after excitation or by a direct excimer to polariton transition. However, for the delayed emission case, trap states are formed on the initially formed triplet manifold, making it evident that an excimer-to-polariton transition has occurred. These results unveil the possibility to control the trap state population by creating a strongly coupled system, which may form a mitigation strategy to counteract detrimental trap states in photonic applications.
强激子 - 光子耦合展现出改变有机分子光物理性质的可能性。这是由于引入了称为极化激元的混合光 - 物质态，其具有独特的物理和光学性质。与裸分子情况相比，那些强耦合系统提供了改变的激发态动力学。在本研究中，我们研究极化激元态与分子陷阱态（如激基缔合物）之间的相互作用。本研究中使用的分子显示出从陷阱态的即时或延迟发射。对于这两种情况，均观察到对激子 - 光子能量调谐的明显依赖性。当系统调谐至较低能量时，极化激元发射逐渐增加，同时聚集诱导发射被消除。对于即时发射，尚不清楚实验结果是最好由激发后向较低极化激元的主要弛豫来解释，还是由直接的激基缔合物到极化激元的转变来解释。然而，对于延迟发射情况，陷阱态在最初形成的三重态流形上形成，这表明明显发生了激基缔合物到极化激元的转变。这些结果揭示了通过创建强耦合系统来控制陷阱态数量的可能性，这可能形成一种缓解策略，以应对光子应用中有害的陷阱态。
