Structure–Property Relationship of Macrocycles in Organic Photoelectric Devices: A Comprehensive Review

Macrocycles have attracted significant attention from academia due to their various applications in organic field-effect transistors, organic light-emitting diodes, organic photovoltaics, and dye-sensitized solar cells. Despite the existence of reports on the application of macrocycles in organic optoelectronic devices, these reports are mainly limited to analyzing the structure-property relationship of a particular type of macrocyclic structure, and a systematic discussion on the structure-property is still lacking. Herein, we conducted a comprehensive analysis of a series of macrocycle structures to identify the key factors that affect the structure-property relationship between macrocycles and their optoelectronic device properties, including energy level structure, structural stability, film-forming property, skeleton rigidity, inherent pore structure, spatial hindrance, exclusion of perturbing end-effects, macrocycle size-dependent effects, and fullerene-like charge transport characteristics. These macrocycles exhibit thin-film and single-crystal hole mobility up to 10 and 26.8 cm² V^-1 s^-1, respectively, as well as a unique macrocyclization-induced emission enhancement property. A clear understanding of the structure-property relationship between macrocycles and optoelectronic device performance, as well as the creation of novel macrocycle structures such as organic nanogridarenes, may pave the way for high-performance organic optoelectronic devices.