Department of Chemistry and Molecular Biology, University of Gothenburg, Kemigården 4, 412 96, Gothenburg, Sweden.
Chemistry. 2020 Nov 11;26(63):14295-14299. doi: 10.1002/chem.202002463. Epub 2020 Oct 1.
Intermolecular interactions play a crucial role in materials chemistry because they govern thin film morphology. The photophysical properties of films of organic dyes are highly sensitive to the local environment, and a considerable effort has therefore been dedicated to engineering the morphology of organic thin films. Solubilizing side chains can successfully spatially separate chromophores, reducing detrimental intermolecular interactions. However, this strategy is also significantly decreasing achievable dye concentration. Here, five BODIPY derivatives containing small alkyl chains in the α-position were synthesized and photophysically characterized. By blending two or more derivatives, the increase in entropy reduces aggregation and therefore produces films with extreme dye concentration and, at the same time almost solution like absorption properties. Such a film was placed inside an optical cavity and the achieved system was demonstrated to reach the strong exciton-photon coupling regime by virtue of the achieved dye concentration and sharp absorption features of the film.
分子间相互作用在材料化学中起着至关重要的作用，因为它们控制着薄膜的形态。有机染料薄膜的光物理性质对局部环境非常敏感，因此人们致力于设计有机薄膜的形态。溶致侧链可以成功地将发色团空间分离，减少有害的分子间相互作用。然而，这种策略也显著降低了可实现的染料浓度。在这里，合成并光物理特性研究了五个含有α-位小烷基链的 BODIPY 衍生物。通过混合两个或更多的衍生物，熵的增加减少了聚集，从而产生了具有极高染料浓度的薄膜，同时具有几乎类似于溶液的吸收特性。将这样的薄膜放置在光学腔中，通过实现的染料浓度和薄膜的尖锐吸收特性，证明所实现的系统达到了强激子-光子耦合状态。
