This report presents a systematic study on the engineering of composite gel heterojunctions, aiming to uncover interfacial charge transport mechanisms and develop high-performance, multifunctional electrochromic devices. First, a viologen ionogel/PProDOT-Me₂ heterojunction system was constructed, elucidating the synergistic electronic/ionic transport mechanism between divalent viologen ions and conjugated polymers, significantly enhancing the optical modulation amplitude of the device. A TiO₂/CdS composite viologen ion gel system was then developed, revealing the photo-/electric-induced interfacial charge transfer mechanism, enabling ultra-low-voltage colour switching and green light adaptive camouflage functionality. Furthermore, a multi-ion natural aqueous BBL electrochromic system was established, overcoming the electrolyte instability challenge in sealed devices and demonstrating excellent cycling stability. This series of studies establishes a methodology for regulating composite gel heterojunctions, providing crucial theoretical foundations and technical support for the design and application of high-performance electrochromic devices.

Viologens,Gel electrolyte,Elcetrochromic devices,photo-electronic effect