Ultrathin Graphite‐Based Full‐Color Electrochromic Devices

Abstract Ultrathin graphite‐based materials have revolutionized optoelectronics through their multispectral and energy‐efficient tunability. However, their narrow color range poses a challenge in applications requiring a broad spectrum of colors for effective information delivery or aesthetic enhancement. Here, full‐color tunability is achieved in ultrathin graphite‐based electrochromic devices using Fabry‐Perot (F‐P) nanocavities. By adjusting the optical properties ( n , k ) of ultrathin graphite through lithium‐ion intercalation/de‐intercalation and the thickness of the dielectronic SiO 2 layer, managed to control the optical reflectivity in the visible spectrum. Moreover, this prototype device consumes only 1.59 mW cm −2 , just one‐tenth of the commercial organic light‐emitting displays’ energy usage. Furthermore, the pixel size in the Fabry‐Perot nanocavity‐type electrodes can be reduced to 2 µm, under half that of contemporary displays like Micro‐LED. These results pave the way for full‐color displays with minimal energy consumption and inspire extensive research in low‐power photonics.