Fabrication of Flexible Electrochromic Devices with Degradable and Fully Recyclable Features

Electrochromic devices (ECDs) are in high demand for many applications; however, there is no ideal method to achieve the full recycling of the substrate and the functional layer in ECDs. Currently, it is still challenging to access ECDs with excellent electrochromic property, good degradability, and facile recycling capability. In this study, high-performance ECDs are successfully fabricated by using poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) as the functional layer and transparent gelatin film (TGF) derived from pigskin as the substrate. Compared with PET films or PET-based ECDs, the optical transmittance of TGF and the coloration efficiency of our ECDs could be increased by 3.2 and 41.4%, respectively, showing a great potential to replace conventional plastic-based ECDs. Furthermore, the TGF not only showed good biodegradability but also could be regenerated via a simple process without the loss of desirable properties. In addition, the functional layer and substrate can be easily separated in water due to the adjusted interactions of the interface and the unique property of gelatin, which may open a new path for fabricating green electronics.