Enhanced Electrochromic Performance of All-Solid-State Electrochromic Device Based on W-Doped NiO Films

Electrochromic materials have attracted much attention due to their promising applications in smart windows and thermal control. However, NiO is a weak point for a complementary ECD and needs to be improved due to its low optical modulation and charge density. In this work, the W-doped NiO films are designed and prepared by RF magnetron co-sputtering to improve the performance of the NiO. The results shows that the optical modulation of the W-NiO (52.7%) is significantly improved compared with pure NiO (33.8%), which can be assigned to the increase in lattice boundaries due to the W doping. The response time of W-NiO is 8.8 s for coloring and 7.2 s for bleaching, which is similar to that of NiO film. The all-solid-state electrochromic devices (ECDs) that employed W-NiO as a complementary layer are prepared and exhibit a high-transmittance modulation of 48.5% in wavelengths of 450–850 nm and an emittance modulation of 0.28 in 2.5–25 µm, showing great application potential in the field of smart windows and spacecraft thermal control devices. The strategy of preparing NiO doped by W indicates an innovative direction to obtain ECDs with high performance.