Tunable and Thermally Stable Luminescence from Polycyclic Aromatic Hydrocarbons Confined in a Zeolitic Imidazolate Framework

Metal-organic frameworks (MOFs) can provide a variety of nanocompartments for the confinement of guest molecules. Furthermore, the emissions of fluorescent molecules can be tuned by confinement. In this study, a solvent-free "bottle-around-ship" method is used to encapsulate perylene and 9,10-dimethylanthracene, two polycyclic aromatic hydrocarbons, in the MOF ZIF-8. Luminescence color tuning is achieved, including white-light emission, when controlling the loading of only a single type of guest. Photophysical analysis suggests that the variations in luminescence result from various guest arrangements in the nanocompartments, as well as host-guest interactions. Because of the tight confinement of the guests, this host-guest system displays excellent luminescence thermal stability.