초록 |
Electrochromic device (ECD) shows reversible color changes as a consequence of electron and ion transfers in the redox reactions. Various electrochromic materials have been studied, and, among these, viologen derivatives have been investigated in-depth due to high electron-accepting capability and facile synthetic routes. However, viologens have suffered from limited electrochromic properties, including slow switching speed, poor long-term stability, and mediocre coloration efficiency. Herein, we present the functionalization of viologen derivatives with the incorporation of polyhedral oligomeric silsesquioxane (POSS), in which the structural rigidity of POSS fillers and the synthetic versatility of viologen compounds are combined. The electrochromic behaviors are thoroughly examined and compared with conventional viologens. Furthermore, flexible and patterned devices are fabricated, and stable electrochromic operations in the repeated redox cycles are demonstrated. |