Enhancing the Solid-State Emission of Carbonyl-Containing Compounds by Means of Introducing a Bifuran Core.

Aromatic aldehydes and ketones are attractive as luminescent materials because they exhibit room temperature phosphorescence. However, an absence of significant luminescence in the solid state limits their practical application. This study investigates a series of bifuran dialdehydes and diketones (F1-F3) and their bithiophene analogues (T1-T3) and compares their photophysical properties in solution and the solid state. The incorporation of carbonyl groups into bifuran cores significantly enhances their solid-state fluorescence, with solid-state quantum yields reaching up to 35%, in contrast to low fluorescence for the thiophene-based analogues. Structural analysis via X-ray crystallography reveals that bifuran derivatives exhibit tighter packing and more rigid molecular backbones, which contributes to the observed aggregation-induced emission. The carbonyl group also stabilizes the furan core compared with unmodified bifurans.