High-durability organic electrochromic devices based on in-situ-photocurable electrochromic materials

Electrochromic materials can undergo electrochemically driven redox processes resulting in optical signal changes, and they have shown attractive application potential in smart windows, wearable electronics, electronic papers, etc. However, their research and development (R&D) are still limited due to the lack of suitable materials and processing strategies to achieve high durability. Here, in-situ-photocurable electrochromic molecules were designed and synthesized to overcome the aforementioned challenges. Compared with the existing doping mode and polymerization mode, in-situ-photocured electrochromic films and devices showed superior durability (e.g., adhesion, multi-dimension stability, and full-contrast calendar life of >120 days) and remarkable overall performance (e.g., transparency = ∼90%, optical modulation = 72.7%, and full-contrast cycle life > 21,000). Furthermore, a high-resolution electrochromic photolithography for micro-nano patterning (recognizable pattern size: ∼2 μm, the best electrochromic resolution to date) was successfully achieved. Based on this, some potential applications in multi-level information encryption and tunable secondary colors were demonstrated.