Tunable and Wide Range Electrically Driven Structural Color‐Changing Device Based on High‐WO₃‐Proportion Inverse Opal Structure

Abstract Inverse opal photonic crystals (IOPC) have great potential in electrically driven device because of their fast response and excellent electrochromic properties. Nevertheless, the conventional IOPC comprises 74% air, which restricts the range of color‐changing. Herein, high‐WO 3 ‐proportion IOPC for the tunable and wide‐range electrically driven structural color‐changing device via a two‐step filling method is fabricated. By utilizing PS@SiO 2 sphere‐assembled opal as sacrificial templates, the filling proportion of WO 3 is significantly enhanced by utilizing the polymer that can swell in (NH 4 ) 6 H 2 W 12 O 40 solution to fill the etched regions of the SiO 2 layer. The fabricated devices exhibit a broad color gamut, enabling a wide color‐changing from 653 nm to 430 nm. The fastest color‐changing rate reached 193 nm −1 s under a reverse voltage of 3.9 V. Moreover, the device has excellent stability, maintaining superior color‐changing capability in 100 cycles. The patterned device significantly enhances its integration, thereby facilitating practical applications.