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.