Tunable low-dimensional self-assembly of H-shaped bichromophoric perylenediimide Gemini in solution

A material with diverse self-assembled morphologies is extremely important and highly desirable because such samples can provide tunable optical and electronic properties, which are critical in applications such as organic photovoltaics, microelectronics and bio-imaging. Moreover, the synthesis and controllable self-assembly of H-shaped bichromophoric perylenediimides (PDIs) are needed to advance these materials in organic photovoltaics, microelectronics and bio-imaging; however, this has remained a great challenge thus far. Here, we successfully synthesize a novel H-shaped bichromophoric PDI Gemini through the palladium-catalyzed coupling reaction. The as-prepared PDI Gemini exhibited unprecedented tunable self-assembly behavior in solution, yielding diverse low-dimensional superstructures, such as one-dimensional (1D) helices, two-dimensional (2D) rectangular nanocrystals, pyramid-shaped parallelograms, ultralarge micro-sheets, and uniform nanospheres, under different self-assembly conditions. Of particular interest, the 2D hierarchical superstructures along with their formation mechanisms represent the first finding in the self-assembly of PDI-based molecules. This study opens a new avenue for tunable self-assembly of conjugated molecules and affords opportunities for the fabrication of novel self-assembled optical and electronic materials based on PDI molecules.