Infrared emittance modulation devices using electrochromic crystalline tungsten oxide, polymer conductor, and nickel oxide

A prototypical small area electrochromic device was fabricated. and emissiv ity was measured from 1 to 30 microns. The devices show change in emissivit y from about 0.60 to about 0.68, that is a total modulation of 13%. The emi ttance performance was calculated, based on the reflectivity modulation. On e difference between these devices and the more frequently explored visible light transmission devices is the utilization of crystalline tungsten oxid e instead of highly disordered amorphous tungsten oxide. The crystalline tu ngsten oxide and nickel oxide charge storage films are characterized by IR transmission/reflection, and spectroscopic ellipsometry. A theoretical mode l has been developed which describes the device performance to within 10% o f experimental results. (C) 1999 Elsevier Science S.A. All rights reserved.