Liquid Crystalline Materials Containing Thiophene Rings

This review article summarizes over 1000 thiophene-based structures with more than 800 liquid crystalline materials (LCMs) in terms of their molecular structures, mesophase, and transition temperatures. It is designed to inform and facilitate the design of novel liquid crystals incorporating thiophene rings for a wide range of technical applications. A spectrum of mesogens incorporating 2,5-disubstituted thiophene rings have been found to manifest an attractive spectrum of physical properties, such as a low melting point and viscosity, large optical anisotropy, fast response times in electro-optic devices, etc. Relationships are elucidated between the presence of a wide range of structural units, such as aromatic cores, linking groups, polar substitutions, and alkyl chains, in the molecular structure of a very wide range of thiophene-based liquid crystalline materials (Thio-LCMs). Many of these Thio-LCMs act as organic semiconductors, exhibiting high charge mobility and strong luminescence for use in a wide range of electro-optical devices. This review is designed to promote the development and optimization of novel heteroaromatic liquid crystals containing thiophene rings, thus stimulating novel mesogenic structural design, enhancing optoelectronic device efficiency, and creating new applications for these advanced functional LCMs.