Structure and Host–Guest Interactions of Perylene–Diimide Dyes in Zeolite L Nanochannels

Confinement-driven self-assembly of dyes in nanomatrices is an effective route for the production of hybrid supramolecular structures of high technological relevance, among which the archetypal zeolite L based systems are exploited in Förster resonance energy transfer (FRET) sensitized solar cells, luminescent solar concentrators, and color-changing media but also in sensing in analytical chemistry, biology, and diagnostics. Despite this progress in applications, the organization of confined chromophores in zeolite L materials remains elusive. Herein, by integrating experiments with different time scale and radiation source (IR, XRPD, total scattering) with first-principles DFT modeling, we attained a microscopically detailed picture of a technologically important hybrid composite of zeolite L with a perylene–diimide (also known as perylene–bisimide) dye at both hydrated and anhydrous conditions. The asymmetric positioning of the dye in the zeolite channel is determined by two factors: shape-volume constraints, and relative strength of competitive interactions among confined species. Our multitechnique experimental-theoretical approach thoroughly described the supramolecular chemistry of this hybrid material, identifiying possible strategies to further enhance FRET efficiency and improve functionality. This work deepens the understanding of host–guest interactions in dye–zeolite L composites, a key requirement to master the finely tuned mechanisms governing supramolecular organization in confined nanospaces.