Molecular insertion regulates the donor-acceptor interactions in cocrystals for the design of piezochromic luminescent materials

Developing a universal strategy to design piezochromic luminescent materials with desirable properties remains challenging. Here, we report that insertion of a non-emissive molecule into a donor (perylene) and acceptor (1,2,4,5-tetracyanobezene) binary cocrystal can realize fine manipulation of intermolecular interactions between perylene and 1,2,4,5-tetracyanobezene (TCNB) for desirable piezochromic luminescent properties. A continuous pressure-induced emission enhancement up to 3GPa and a blue shift from 655 to 619nm have been observed in perylene-TCNB cocrystals upon THF insertion, in contrast to the red-shifted and quenched emission observed when compressing perylene-TCNB cocrystals and other cocrystals reported earlier. By combining experiment with theory, it is further revealed that the inserted non-emissive THF forms blue-shifting hydrogen bonds with neighboring TCNB molecules and promote a conformation change of perylene molecules upon compression, causing the blue-shifted and enhanced emission. This strategy remains valid when inserting other molecules as non-emissive component into perylene-TCNB cocrystals for abnormal piezochromic luminescent behaviors. The design of piezochromic luminescent materials with desirable stimuliresponsive properties remains challenging. Here, the authors report the insertion of a non-emissive molecule into a donor and acceptor binary cocrystal and realize desirable piezochromic luminescent properties by manipulation of intermolecular interactions between the donor and acceptor molecules.

Automated summary

Developing a universal strategy to design piezochromic luminescent materials with desirable properties remains challenging. Here, the authors report the insertion of a non-emissive molecule into a donor and acceptor binary cocrystal and realize desirable piezochromic luminescent properties by manipulation of intermolecular interactions between the donor and acceptor molecules. This strategy allows for continuous pressure-induced emission enhancement and blue shift in the emission wavelength.