Synthesis and Optoelectronic Properties of Perylene Diimide-Based Liquid Crystals

Perylene diimide (PDI), initially synthesized and explored as an organic dye, has since gained significant recognition for its outstanding optical and electronic properties. Early research primarily focused on its vibrant coloration; however, the resolution of solubility challenges has revealed its broader potential. PDIs exhibit exceptional optical characteristics, including strong absorption and high fluorescence quantum yield, along with remarkable electronic properties, such as high electron affinity and superior charge carrier mobility. Furthermore, the robust π-π stacking interactions and liquid crystalline behavior of PDIs facilitate precise their self-assembly into highly ordered structures, positioning them as valuable materials for advanced applications in optoelectronics, photonics, and nanotechnology. This article provides a comprehensive review of the progress made in the design, synthesis, and optoelectronic performance of PDI-based liquid crystals. It explores how various substituents and their placement on the PDI core impact the properties of these liquid crystal molecules and discusses the challenges and opportunities that shape this rapidly evolving class of optical materials. This review is strictly focused on PDIs and does not cover their elongated or laterally extended derivatives, nor does it include monoimide or ester compounds.