Cuttlefish-inspired smart window by dielectrophoresis of nanoparticles dispersed in the asymmetric dielectric media

We propose a bioinspired smart window based on dielectrophoresis (DEP). DEP refers to the motion of polarizable particles in a non-uniform electric field. In our design, a gradient electric field is generated by introducing asymmetric dielectric media sandwiched between non-patterned electrodes. By utilizing the dielectrophoretic behavior of nanoparticles confined within a transparent polymer film featuring inverse pyramidal microstructures, we demonstrate dynamic modulation of optical transmittance. The refractive index of the dielectric medium is matched to that of the transparent polymer, enabling high transparency in the clear state. When an electric field is applied, the nanoparticles are driven toward the edges of the microstructures, reducing light absorption area and enhancing transmittance. When the field is removed, the nanoparticles re-disperse, leading to increased light absorption and decreased transmittance. We systematically investigate the performance of the smart window by varying nanoparticle concentration and geometric parameters, supported by numerical simulations using the finite element method (FEM).