Thermally Activated Delayed Fluorescence Macrocycles for Organic Light‐Emitting Diodes

Macrocyclic compounds have garnered considerable attention in the realms of supramolecular chemistry and optoelectronic materials owing to their distinctive geometries, exceptional stability, and potential chiral properties. As third‐generation organic light‐emitting diodes (OLEDs) emitters, thermally activated delayed fluorescence (TADF) materials present themselves as promising contenders due to their ability to achieve complete exciton utilization through the harnessing of triplet excitons. The incorporation of macrocyclic structures with TADF characteristics holds the potential to yield TADF emitters endowed with unique attributes, thereby synergistically enhancing the performance and longevity of TADF materials for diverse device applications, ultimately propelling their commercialization. Within this comprehensive review, a thorough exploration of the molecular structures, synthesis methodologies, structure‐property relationships, and applications of the reported macrocyclic TADF systems in OLEDs are delved. Additionally, the prevailing challenges and prospective research directions are highlighted that demand attention in the realm of macrocyclic TADF materials. It is hoped that this review will provide researchers engaged in optoelectronic materials research with a lucid comprehension and inspiration concerning the intricacies of these macrocyclic TADF systems. TADF macrocycles are classified into four distinct categories: TICT‐TADF, TSCT‐TADF, MR‐TADF macrocycles, and macrocycles for TADF exciplexes. This comprehensive review aims to provide valuable insights into the world of macrocyclic TADF systems, offering a clear understanding and inspiration for researchers in the field of optoelectronic materials.