A Bistable Variable Infrared Emissivity Device Based on Reversible Silver Electrodeposition

Abstract Reversible silver electrodeposition (RSE) can dynamically modulate visible light and infrared radiation through the reversible electrodeposition and dissolution of silver layer. However, the RSE device with bistability better than 2 h has not been reported, because the deposited silver layer may dissolve automatically without driving voltage. Here, a variable infrared emissivity device based on RSE with 24 h excellent bistability is demonstrated. A silver layer fixed at the counter electrode is used as the charge mediator, which reforms the electrochemical reactions of the counter electrode and is the key for obtaining bistability. Effects of electrolyte composition and driving voltage on the bistability are studied, and the driving voltage affects the bistability of RSE devices. This RSE device can be enlarged to 5 × 5 cm² with uniform emissivity change of 0.48 in 2.5–25 µm using silicon wafer as the infrared transparent working electrode substrate, and display discontinuous thermal patterns through incorporating a dielectric pattern layer. The cyclability and device failure mechanism is analyzed. With the excellent bistability, the proposed RSE devices provide great application prospects in the fields of dynamic infrared information display, adaptive infrared camouflage, and smart thermal management.