Design of blue fluorescence emitter star-shaped macromolecules based on pyrene and anthracene.

Star-shaped macromolecules decorated with fluorescence moieties such as pyrene and anthracene have been developed, which exhibit aggregation enhanced excimer emission (AEEE). The presented star-shaped macromolecules showed only weak emissions in the visible region in dilute solution, due to the predominance of the monomer emission, which has its maximum in the UV-A region of the spectrum. However, the strong blue visible excimer-like emission is generated in the aggregated state, by the use of poorly solubilizing solvents or high concentration. The solution of these macromolecules emitted blue light centred at 475 and 474 nm with pyrene and anthracene moieties respectively. In addition, emission efficiency increases were observed with increasing water fraction. The unique phenomenon of AEEE was verified by determining the excimer-monomer emission intensities ratio (I E /I M ). TEM was used to detect the difference between the aggregation states in various THF/water ratios. The molecular structures of the fluorescent star were investigated using (MMFF). [ABSTRACT FROM AUTHOR]