Wide‐Temperature Full‐Color Electrophoretic Colloidal Crystal Displays With High Color Saturation

Electrophoretic colloidal crystal displays (ECCDs) hold great potential in next‐generation sustainable, low‐energy full‐color reflective displays, yet their practical development has been hindered by sluggish switching dynamics and poor operability at low temperatures. Here, we report a wide‐temperature, low‐power electrophoretic color display based on tailored carbon shell‐coated polystyrene nanospheres (PS@C) in a modified deep‐eutectic‐solvent (MDES) dielectric medium. Under an applied electric field, PS@C nanospheres form highly ordered 3D colloidal crystals with ideal stopbands due to their narrow size distribution and high effective refractive index (∼1.67). Mimicking melanin‐based photonic structures in peacock feathers, the PS@C nanospheres enable vivid structural colors with high purity and brightness. The system exhibits dynamic color switching from a dark‐brown off‐state to full‐color states. It also enables reversible red‐to‐blue color modulation over a spectral range of 160 nm, with a fast tuning rate of ∼267 nm s −1 . The MDES‐mediated ECCD demonstrates reliable device operation over a wide temperature range from 45°C down to −20°C. This presents unique application prospects in fields such as cold‐chain logistics displays and outdoor electronic tags in cold regions.