Dynamic Multicolor Display with Wide Color Gamut Enabled by Vanadium Oxide-Based Fabry–Pérot Electrochromic Nanocavities

Abstract

Inorganic electrochromic (EC) devices with vibrant multicolor variations are at the forefront of EC technology and play a crucial role in display applications. Expanding the dynamic color gamut of a single EC device has long been a subject of investigation. Herein, a design is presented that employs vanadium oxide (VO_x) as the EC layer and tungsten (W) as the reflective layer to construct an asymmetric Fabry–Pérot (F–P) nanocavity, enabling wide color gamut EC displays. By leveraging the different thicknesses of VO_x, this design allows for a range of color changes from yellow and orange to magenta, purple, blue, cyan, and green through dynamic EC modulation. Notably, a typical single W-VO_x (150 nm) F–P nanocavity demonstrates an impressive modulation range of 110 nm, exceeding the capabilities of existing F–P nanocavities. In-depth structural analysis reveals that the insertion and extraction of Li⁺ ions significantly influence the microstructure and optical properties of VO_x film, allowing for greater refractive index adjustment than WO₃. This facilitates precise control and expansion of the nanocavity's color range through interference effects. This study provides a new perspective for developing dynamically adjustable wide color gamut EC displays and highlights their potential applications in flexible display technologies.