Entropic Mixing Allows Monomeric‐Like Absorption in Neat BODIPY Films. Issue 63 (1st October 2020)

• Record Type: Journal Article
• Authors: Schäfer, Clara; Mony, Jürgen; Olsson, Thomas; Börjesson, Karl
• Is Part Of: Chemistry. Volume 26:Issue 63(2020)
• Page Start: 14295
• Page End: 14299
• Publication Date: 2020-10-01
• Subjects: BODIPY -- chromophores -- entropic mixing -- morphology -- strong exciton-photon coupling; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202002463
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: 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. Abstract : Entropic mixing of two or more, highly similar dye molecules results in thin films showing almost solution like photophysical properties. Mixed films of new, low molecular weight BODIPY dyes, with short alkyl chains, were fabricated and furthermore used in an optical cavity, where the strong coupling regime was reached.