Through-Space Conjugation: A Thriving Alternative for Optoelectronic Materials

Abstract

Efficient electronic coupling is the key to constructing optoelectronic functional π systems. Generally, the delocalization of π electrons must comply with the framework constructed by covalent bonds (typically σ bonds), representing classic through-bond conjugation. However, through-space conjugation offers an alternative that achieves spatial electron communication with closely stacked π systems instead of covalent bonds thus enabling multidimensional energy and charge transport. Because of the ever-accelerating advances of through-space conjugation studies, researchers are inspired greatly by the beauty of through-space conjugated systems and their potential in high-tech applications. In this mini review, we introduce some representative and newly developed π systems having the through-space conjugation feature. In addition to discussing the profound impacts of through-space conjugation on the luminescence properties and charge transport, we will review some impressive findings of distinctive molecules with attractive characteristics, such as aggregation-induced emission, thermally activated delayed fluorescence, bipolar charge transport, and multichannel. These achievements may bring about new breakthroughs of theory, materials, and devices in the fields of organic electronics and molecular electronics.