Making color display cool: An electrochemical self-cooled dynamic structural color device

Abstract

Electrochromic (EC) materials can dynamically manipulate transport of light and thermal radiation under the electric field, which are promising for applications such as smart windows and energy-saving display devices. The color switching mechanism in EC materials is mainly based on optical absorption, resulting in excessive solar thermal load when used outdoors. Although daytime radiative cooling (DRC) provides a possible solution for energy-efficient heat dissipation for these outdoor devices, it often leads to a white appearance incompatible with EC color displays. To address this challenge, we develop novel display devices that can simultaneously realize color switching and DRC, enabled by reconfigurable, high-quality optical nanocavities based on reversible metal electrodeposition. These devices can not only achieve sub-ambient cooling of 2.6 ~ 5.3 ℃ under direct sunlight but also exhibit multiplexed adaptive displays with diverse colors, high stability, and long cycle life. Based on worldwide building-level energy simulations, we show this novel display can potentially save electrical energy consumption of 0.8–23.1 kWh/m2 compared to conventional LED displays, providing a new paradigm of passively cooled dynamic color display.