VIS-IR electrochromic device with electromagnetic wave absorption function based on a Fe3O4@PANI composite material†
Abstract
To further broaden the applicable band of electrochromic devices, a counter electrode with electromagnetic wave absorption function was developed. A ferrosoferric oxide (Fe3O4)@Polyaniline (PANI) composite material with a core–shell structure was prepared by oxidative polymerization. The relative content of PANI and Fe3O4 and its impact on the electromagnetic wave absorption performance of the Fe3O4@PANI composite material were analyzed. The absorption bandwidth of the electromagnetic wave absorption counter electrode based on Fe3O4@PANI/polyvinylidene difluoride (PVDF) reached 3.5 GHz (14.5–18.0 GHz, RL < −10 dB), and it can provide a sufficient amount of counter ions to balance the charge of the electrochromic layer. The visible-infrared (VIS-IR) electrochromic device with an electromagnetic wave absorption function on the counter electrode exhibits color changes to yellow, green, and dark green on the side of the electrochromic layer, and has an emissivity change of 0.43 in the thermal infrared band wavelength range of 2.5–15 μm. The coloring and fading response times of the device are 5.9 s and 4.4 s, respectively, and the device maintains 95.7% of the initial current intensity after 1000 cycles.