Colorful Electrochromic Displays with High Visual Quality Based on Porous Metamaterials

The introduction of metamaterials into electrochromic (EC) displays has recently inspired a great breakthrough in the EC field, as this can offer a variety of new attractive features, from a very wide gamut of colors to very fast switching times. However, such metamaterial-based EC displays still face significant constraints when developing from single electrodes to full devices, because other supportive components in devices, such as counter electrodes and electrolytes, significantly affect light propagation and the subsequent perceived color quality in metamaterial-based EC devices. Herein, a new, cost-effective device design structured around a new type of porous metamaterial is reported to circumvent the critical problem in metamaterial-based EC displays. Owing to its unique design, the metamaterial-based EC device achieves good color quality with no drop in brightness or shift in color chromaticity when compared with a single electrode. Moreover, the porous-metamaterial-based EC device can exhibit non-iridescence and be viewed from a wide range of angles (5°-85°) and has fast switching response (2.4 and 2.5 s for coloration and bleaching, respectively), excellent cycling performance (at least 2000 cycles), and extremely low power consumption (4.0 mW cm^-2 ).