氟化烷基紫精凝胶器件的制备及电力设备微电流可视化检测应用

Electrochromic（EC）materials，which convert electrical signals into visual optical signals，hold great promise in smart sensing applications. Viologens are classic EC materials but face challenges in cycling stability and solid-state device fabrication. In this work，three alkyl viologen derivatives with varying fluorination degrees were designed and synthesized：1，1'-trifluorodipropyl-4，4'-bipyridinium（PV（3F）），1，1'pentafluorodibutyl-4，4'-bipyridinium（BV（5F）），and 1，1'-heptafluorodipentyl-4，4'-bipyridinium（AV（7F））. First-principles calculations revealed that increasing fluorine atoms narrows the HOMO-LUMO gap from 4. 56 eV to 3. 79 eV，facilitating electron transition and charge transfer. Electrochemical tests confirmed that fluorination significantly enhances electrochemical activity and electron transfer kinetics，with AV（7F）exhibiting a diffusion coefficient of 3×10^-5 cm²/s and an electron transfer rate constant of 1. 3×10^-3 cm/s. All-solid-state gel EC devices were fabricated by incorporating the fluorinated viologens into a poly（vinylidene fluoride）（PVDF）matrix. Among them，the AV（7F）/PVDF device demonstrated superior comprehensive performance：an optical contrast of 76% at 600 nm，a coloration efficiency of 162 cm^2/C，coloration/bleaching response times of 3 and 29 s，respectively，and a pure deep blue colored state . Electrical property measurements showed that the gel composite possesses an appropriate dielectric constant（~13. 8 at 20 ℃，50 Hz）and volume resistivity（~10⁸ Ω·cm），meeting insulation requirements. When applied in simulated current sensing experiments，the gel device exhibited distinct color changes upon micro-current stimulation，with the degree of coloration positively correlated with current intensity. These results preliminarily validate its potential for visual micro-current detection in power equipment.