Due to the highly ordered order of molecules in the liquid crystal material, it has a relatively high electron and hole mobility that does not change with the external electric field and temperature. At the same time, due to the self-alignment ability of liquid crystal molecules, it is easy to fabricate thin-film devices with a high degree of molecular order in a large area. As an optoelectronic device material, liquid crystalline semiconductor has excellent charge and energy transfer characteristics and anisotropy. Among the many liquid crystal materials, the columnar phase formed by the discotic liquid crystal constitutes the carrier channel formed by the overlap of the electron cloud, which can carry out the charge and energy transfer in a specific direction. Therefore, the discotic liquid crystal has excellent electrical conductivity as an organic semiconductor.
Figure 1. The chemical structure of some liquid crystalline semiconductors
- Semiconductor laser: The narrow linewidth, tunable, and frequency stable external cavity semiconductor lasers are widely used in the fields of atomic clocks, heterodyne sensor measurement, optical fiber sensing, and photoelectron detection. The liquid crystalline semiconductor material can make the OFET device made by using an external electric field to control the internal molecular orientation of the liquid crystal to obtain a stable tuning method. It has the following advantages: (1) The applicable spectral range is extremely wide; (2) The voltage required for tuning is small and the response time is fast; (3) There is no undesirable mechanical movement.
- Light control material: As the core material of photosensitive OFET functional devices, light control materials play an important role. In liquid crystalline semiconductors, the powerful π-π conjugate system of acene materials makes it exhibit excellent device performance. As a solution-processable high-performance UV-responsive organic semiconductor, liquid crystalline semiconductors has a wide range of applications in flame detection, space safety communications, combustion engineering, water purification treatment, etc. It has the advantages of high sensitivity, fast response, low noise, small size, and low power consumption, and significantly improves the performance of light control materials.
- Yu-Jie Zhong,Ke-Qing Zhao,Bi-Qin Wang,Ping Hu,Hirosato Monobe,Benoît Heinrich,Bertrand Donnio. 2-Phenylbenzothiophene-based liquid crystalline semiconductors [J]. Dyes and Pigments 2020, 173, 107964.