Figure 2
From: Energy transfer in supramolecular materials for new applications in photonics and electronics
(a) It is often the case that two urea residues appended to a π-conjugated core, such as a phenylenethiophene unit (UPT), induce the formation of stacked assemblies and the formation of fibrilar gels (crystal structure and atomic force microscopy image below). Adapted with permission from reference Dautel et al.38 (b) The use of two biuret hydrogen-bonding (H-B) units code for the spontaneous formation of hollow spheres in solution that persist upon solvent evaporation (scanning electron micrograph, bottom). This is attributed to the existence of two H-B sites on each biuret unit that are orthogonal to one another (labeled A and P). Compounds BU-1, BU-2 and BU-3 emit in the blue, yellowish green and red region of the spectrum and can be combined in a single vesicle to produce light of any color contained in the dashed triangle. Adapted with permission from reference Tseng et al.39
