Highly luminescent ladder dimer based on perylene diimides and norbornane

Solution processable functional ladder-type materials with well-defined structures attract tremendous interest from the researchers due to their extraordinary stability and intriguing photoelectric properties, while the development of efficient and versatile synthetic routes still remains as an enormous challenge. Herein, we report a novel synthetic strategy towards a ladder-type PDI dimer by efficient photo-cyclization reaction of the single stranded precursor. The incorporation of the norbornane bridge endows the ladder dimer with planar PDI units, zigzag molecular conformation, and good solubility in various solvents. Besides superior thermal and photostability, LPD exhibits fluorescent quantum yields (QY) of 90.8% and 25.7% in solution and film, respectively. Both values are significantly higher than those of the single-stranded counterpart SPD (85.1% and 7.5%).