Rescuing the solid-state fluorescence of perylene diimide dyes by host–guest isolation

Abstract

Fluorescence quenching in solid state is a long-standing problem in dye chemistry, wherein perylene diimide (PDI) dyes are one of the trickiest classes of dyes due to their strong propensity of face-to-face self-aggregation. Here we report a new host molecule (1) that is capable of regulating the aggregation behaviour and fluorescence properties of various PDI dyes in solid state via host–guest isolation. Through UV-vis, NMR and fluorescence studies, we demonstrate for the first time the universality of a host, 1, in recognizing different PDI dyes. A simulated NMR structure based on NOE correlations provides the structural evidence of host–guest isolation. The ability of 1 to rescue the quenched fluorescence of PDI dyes in solid state is carefully verified by comparing UV-illuminated images and quantum yields of PDI + 1 with those of PDI alone. Remarkably, all the tested PDI dyes, with different sizes and diverse substituents, show greatly enhanced fluorescence after the addition of 1. Finally, after testing other popular hosts, the unique universality of 1 in rescuing the solid-state fluorescence of PDI dyes is shown.