| 摘要(英) |
In general, liquid crystal technology often utilizes dye doping and Bragg reflection bandwidth to manage light absorption or color change. However, research on combining liquid crystals with an electrochromic layer to achieve dimming and color modulation is relatively scarce. Therefore, this study mainly explores the combination of an electrochromic layer with liquid crystal technology to create a novel display technology that incorporates the advantages of both. Firstly, this study attempted to use positive liquid crystal E7 doped with ion salt LiClO_4 to provide ions for the redox reactions in electrochromism, creating a liquid crystal electrochromic device by combining it with an electrochromic layer. However, it was found that the spontaneous vertical alignment of ions caused the liquid crystal to lose its birefringence. To address this issue, the study replaced the positive liquid crystal with negative liquid crystal HNG30400-200 and doped it with chiral dopants S811 to form a helical structure, enhancing ion migration. This device exhibited four operating states: colorless transparent, colored transparent, colored scattering, and colorless scattering. However, issues such as high operating voltage and unsatisfactory color uniformity persisted. The study then focused on improving electrochromic performance by comparing the effects of three ionic liquids: [Bmim][NTf2], [Bmim][PF6], and [Emim][BF4], as electrochromic electrolyte layers. It was found that [Bmim][PF6] was more suitable within the framework of this study, yet it still exhibited a slow and incomplete bleached state. Therefore, UV-curable electrolytes were used to create electrochromic devices with better performance, showing a transmittance change from 8.88% to 69.12% at 638.8 nm and demonstrating good switching speed and memory effect. By doping dichroic dyes AG1, AZO1, and S-428 into the liquid crystal and combining them with the electrochromic devices developed in this study, the feasibility of combining liquid crystal and electrochromic layers was verified, achieving dimming and color modulation. Among them, the device of liquid crystal doped with S-428 combined with the electrochromic layer showed the best dark state with an overall transmittance as low as 2.93% across the wavelength band between 400 nm and 800 nm. Due to its high dynamic range and good visibility, it has potential applications in the development of wearable devices such as AR/VR.
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