Advances in star-shaped π-conjugated systems: properties and applications

Until recently π-conjugated organic materials are based mainly on linear systems. Recent years, however, have brought about increasing interest in molecules boasting a dendritic, branched, or star-shaped architecture. This tendency is a direct result of the ongoing search for materials with progressively better properties. Such compounds, featuring novel, 3D architectures, exhibit a multitude of interesting qualities, making them stand out from well-known materials. The direction of star-shaped compound application is determined by whether they are able to form aggregates, π-stacks. This feature is a source of some astounding properties, coveted in numerous applications. Among this class of compounds high charge mobility, high fluorescence efficiency, and good charge separation are all found. Depending on the structure of the core, the molecule may adopt various types of symmetry. Similarly, the conjugation of orbitals may extend over the whole structure or be interrupted at chosen segments. The number of papers pertaining to star-shaped oligomers and polymers is ascending with each year, evidencing a growing interest in them. Consequently, this Review focuses particularly on the most recent reports concerning modification of the structure and properties of the aforementioned type of compounds, as well as on the development of devices based on them.