Variable Electrochromic Devices (VEDs) for Space Simulation Testing

Physical Sciences Inc. (PSI) proposes to fabricate two electrochromic (EC) devices during the proposed Phase I program. PSI will fabricate an EC infrared reflector based on poly(alkyl-propylene dioxythiophene) (alkyl-ProDOT). PSI has several alkyl-PProDOT compounds in stock from past EC programs that will be examined for infrared electrochromism at 120 K. The solution processable alky-PProDOTs are expected to provide 2 to 7 micron bandpass transmission contrast of 15 to 80%, for a 160 nm thick reflector overcoat film. Lower contrast can be achieved out to 12 microns using these polymers. An EC infrared beamcombiner will be constructed using a tungsten oxide based EC film. The tungsten oxide based beam combiner is expected to operate between 50/50 and up to 90/10 reflection/transmission contrast at 2 to 7 micron wavelength bandpass. Lower contrast can be achieved out to 10 microns using this tungsten oxide. These optical elements will be optimized for switching speed at 120 K, while maintaining bandpass and contrast requirements. Hermetic packaging will permit vacuum operation. A Phase II program will extend the reflector and beam combiner operation down to 20 K, and further optimize optical performance. The Phase II program will also examine the EC devices for operation using visible light.