Electro-optic properties of graphene oxide liquid crystals in organic solvents

Aqueous graphene oxide liquid crystals (GO-LCs) have demonstrated promising applicability in low-power display technologies owing to their extremely large Kerr coefficient. However, the electro-optic properties of GO dispersed in organic solvents have not been systematically investigated. In this study, the electro-optic properties of GO dispersed in organic solvents N, N-dimethylformamide (DMF), ethanol, N-methyl-2-pyrrolidone (NMP) and isopropyl alcohol (IPA) were systematically investigated. Lyotropic liquid crystalline phase behavior was confirmed in DMF, ethanol and NMP, and their electro-optic properties were evaluated. The results showed that GO dispersed in DMF exhibited the largest Kerr coefficient, which was contributed to the lowest conductivity of DMF. A comparison of the optical transmittance of GO-LCs revealed that the solvent significantly influenced the absorbance spectrum in the visible range. The electro-optic performance at different frequencies was further investigated. Unlike aqueous GO-LCs, organic solvent GO-LCs displayed stable electro-optic switching behavior from 0.1 kHz to 1 kHz without electrolysis. Response time measurements indicated that the on time was primarily determined by solvent viscosity, whereas the off time was influenced by solvent permittivity. This work elucidates the intrinsic correlation between the solvent physical properties and the electro-optic performance of organic solvent GO-LCs. These findings establish a theoretical foundation for the design and development of high-performance GO-LCs intended for advanced electro-optic devices.