All-solid-state electrochromic reflectance device for emittance modulation in the far-infrared spectral region

Authors

• E. B. Franke, University of Nebraska-LincolnFollow
• C. L. Trimble, University of Nebraska-Lincoln
• Mathias Schubert, University of Nebraska-LincolnFollow
• John A. Woollam, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

8-14-2000

Comments

Published in Appl. Phys. Lett., Vol. 77, No. 7, 14 August 2000. © 2000 American Institute of Physics. Used by permission.

Abstract

All-solid-state electrochromic reflectance devices for thermal emittance modulation were designed for operation in the spectral region from mid- to far-infrared wavelengths (2–40 μm). All device constituent layers were grown by magnetron sputtering. The electrochromic (polycrystalline WO₃), ion conductor (Ta₂O₅), and Li⁺ ion-storage layer (amorphous WO₃), optimized for their infrared (IR) optical thicknesses, are sandwiched between a highly IR reflecting Al mirror, and a 90% IR transmissive Al grid top electrode, thereby meeting the requirements for a reversible Li⁺ ion insertion electrochromic device to operate within the 300 K blackbody emission range. Multicycle optical switching and emittance modulation is demonstrated. The measured change in emissivity of the device is to 20%.