In this study, the electrochromic property of vinyl benzyl viologen (VBV) was first investigated and incorporated in an electrochromic device (ECD). The polymerizable vinyl moiety of VBV enables a self-immobilization through UV-curing under potential bias. Immobilized VBV (I-VBV) was obtained on the electrode and grafted with polymer electrolyte. An ECD consisted of Prussian blue (PB), I-VBV, and ferrocene (Fc) was fabricated (PB/Fc/I-VBV ECD) in which Fc acted as a redox mediator. With the utilization of polymer electrolyte, Fc, and immobilization of VBV, the proposed PB/Fc/I-VBV ECD with a UV-curing time of 40 s (PB/Fc/I-VBV-40) exhibited the best cell performance among all conditions in terms of long-term stability. It gives 60.6% transmittance change (δT) at 615 nm initially when switched between 1.2 V and -0.8 V. Short bleaching and coloring times of 1.32 s and 2.13 s were achieved respectively. Moreover, good long-term stability was obtained, maintaining 86.5% of its original δT after 10,000 cycles. The PB/Fc/I-VBV ECD also exhibited a unique memory characteristic among all viologens-based ECDs reported in literatures and allowed the possibility for tuneable multi-electrochromism.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films