Highly fluorescent free-standing films assembled from perylenediimide microcrystals for boosting aniline sensing†
Molecular assembly has emerged as a key protocol for designing functional materials, although building in task-specific applications remains challenging. Here, a simple solvent-diffusion fabrication of highly fluorescent free-standing films (FFSFs) obtained from perylenediimide (PDI) microcrystals is described. The high fluorescence intensity of the resulting FFSFs follows from the mode of solid-state packing of the PDI molecules. The porous, crystalline FFSFs provide increased surface area and enable unobstructed diffusion of guest molecules for boosting aniline sensing with low detection limit, high selectivity and reversibility. Density functional theory (DFT) calculations indicate that the fluorescence quenching is caused by photoinduced electron transfer (PET). The new FFSFs furnish amplified discrimination of analytes and represent a major step ahead toward the rational synthesis of assembled sensing materials.