Effects of Heavy p-Block Elements on Photophysical Properties of π-Conjugated Complexes and Organoelement Compounds

Abstract

π-Conjugated compounds exhibit remarkable photophysical properties, such as strong light absorption and emission, and are applicable to organic devices, bioimaging, and sensing systems. The introduction of p-block elements into π-conjugated systems is presumable as a critical strategy for modulating their properties. Nevertheless, the type of utilized elements has been limited to the second and third-period ones because it is difficult to construct critical electronic interactions between heavier atoms and carbon-based π-conjugated scaffolds. On the other hand, it has been recently suggested that the heavier p-block elements are able to induce significant changes in the optoelectronic properties of π-conjugated systems thanks to their large size, high polarizability, and heavy atom effect. Although there are much room to explore effects of heavy-atom substitution on physical and electronic properties of conjugated systems, various characters have been discovered. Hence, this review mainly focuses on the relationships between the types of p-block elements and the optical properties of their representative complexes and organoelement compounds, particularly light absorption and emission.