Brilliant, stable, and electrically responsive photonic crystals based on dielectric particles and solvation repulsion.

Electrically responsive photonic crystals (ERPCs) capable of adjusting their structural colors in response to electric fields are promising next-generation smart optical materials. However, the poor color saturation and stability of conventional ERPCs significantly limit their practical applications. Here, a new kind of ZnS-silica/diethylene glycol ERPC was designed and fabricated by directly non-close-assembling ZnS-silica core-shell particles with high refractive indexes into a diethylene glycol with a low dielectric constant. Compared to traditional ERPCs, the as-fabricated ERPC exhibits: 1) brilliant structural colors and broad photonic bandgaps, owing to the large refractive index contrast; and 2) good stability under voltages, improved at least two magnitude, due to the combined intense solvation repulsion and enhanced electrostatic repulsion. This work provides new insight for designing and fabricating advanced ERPCs and will promote their practical applications in low-power displays, anti-counterfeiting, and optical devices.