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

All-solid-state electrochromic reflectance devices for thermal emittance mo dulation were designed for operation in the spectral region from mid- to fa r-infrared wavelengths (2-40 mu m). All device constituent layers were grow n by magnetron sputtering. The electrochromic (polycrystalline WO3), ion co nductor (Ta2O5), and Li+ ion-storage layer (amorphous WO3), optimized for t heir infrared (IR) optical thicknesses, are sandwiched between a highly IR reflecting Al mirror, and a 90% IR transmissive Al grid top electrode, ther eby meeting the requirements for a reversible Li+ ion insertion electrochro mic device to operate within the 300 K blackbody emission range. Multicycle optical switching and emittance modulation is demonstrated. The measured c hange in emissivity of the device is to 20%. (C) 2000 American Institute of Physics. [S0003-6951(00)01733-2].