The rapid advancement of optical communication technologies and optoelectronic display industry has highlighted the limitations of conventional nematic liquid crystal materials regarding response speed. The current millisecond-scale response time of liquid crystal materials fails to meet the requirements of high-performance devices for fast dynamic response, while limiting the performance enhancement of high-speed optical communication modulation devices. To address this technical challenge, this study examines a novel ferroelectric nematic liquid crystal material DIO, systematically investigating its electro-optical response characteristics under wide temperature range (40?68 ℃) and low driving electric field conditions, and exploring the relationship among response characteristics, voltage, and temperature. This research provides novel technical solutions to overcome the key limitations of slow response speed and high driving voltage in traditional liquid crystal materials, while establishing theoretical foundations and practical guidelines for developing next-generation high-performance optoelectronic display devices and high-speed optical communication components.

This study employed a combined approach of theoretical analysis and experimental verification. The theoretical framework was based on the physical mechanism of the Frederiks transition effect, describing liquid crystal molecular reorientation under applied electric fields, and the synergistic mechanism between dielectric anisotropy and elastic constants was analyzed. The experimental design incorporated an innovative liquid crystal cell with a cross-shaped electrode structure. This design addressed the limitations of traditional parallel-plate electrodes and enabled multidimensional precise control of liquid crystal molecular orientation. Electric field distribution of the cross-shaped electrode structure was simulated using MATLAB software. The simulation results confirmed that this design generated a uniform in-plane electric field, supporting the experimental findings. The experimental setup utilized polarized optical microscopy for texture change observation during molecular reorientation, photodetectors for transmittance intensity measurements, and high-bandwidth digital oscilloscopes for response waveform recording. This configuration enabled comprehensive monitoring of key parameters including liquid crystal director rotation process and transmittance intensity changes. Through controlled variable experiments, the study systematically examined the dynamic response characteristics of DIO material under various electric field conditions and temperature ranges, analyzing their correlations.

The ferroelectric nematic liquid crystal DIO exhibits remarkable electro-optical response properties. Specifically, it demonstrates stable and fast switching under an ultralow driving electric field of 2×10? V/m across a broad temperature range of 40?68 ℃ (Fig. 6). This required electric field strength is four orders of magnitude lower than that of conventional nematic liquid crystals and two orders of magnitude lower than polymer-stabilized liquid crystals, substantially reducing the driving voltage requirements (Table 1). In terms of dynamic response, DIO shows microsecond-scale fast switching characteristics, with rise time and decay time of approximately 500 μs and 650 μs, respectively. Moreover, the transmitted light intensity increases significantly while the response time decreases markedly with increasing DC voltage, pulse voltage, and temperature (Fig. 6).

This study systematically investigated the microsecond-scale electro-optical response capability of ferroelectric nematic liquid crystal DIO based on the Frederiks transition principle. Experimental results reveal that increasing DC voltage, pulse voltage and temperature leads to enhanced transmittance intensity and reduced response time. DIO demonstrates significant advantages in both low driving electric field and wide temperature range operation compared to conventional nematic liquid crystals, polymer-stabilized liquid crystals and other ferroelectric nematic liquid crystals. The material’s excellent performance under wide temperature ranges and low driving voltages suggests promising applications in next-generation liquid crystal displays, liquid crystal lenses, and optical switching devices. However, DIO exhibits performance degradation below 45 ℃, primarily due to increased viscosity coefficient and decreased dielectric anisotropy at low temperatures. Future research directions may include improving the material’s room temperature performance through molecular structure modification by incorporating flexible groups to lower phase transition temperature, or developing DIO-based composite materials to enhance low-temperature response performance.