AT PRESENT THERE ARE NO SPECTRALLY SELECTIVE SURFACES AVAILABLE FOR PHOTOTHERMAL APPLICATIONS WHICH CAN HAVE THEIR SELECTIVITY CHANGED DURING OPERATION OF SOLAR COLLECTORS.

AT PRESENT THERE ARE NO SPECTRALLY SELECTIVE SURFACES AVAILABLE FOR PHOTOTHERMAL APPLICATIONS WHICH CAN HAVE THEIR SELECTIVITY CHANGED DURING OPERATION OF SOLAR COLLECTORS. SUCH AN ADJUSTMENT WOULD PERMIT CONTROL OF THE TEMPERATURE OF THE COLLECTOR IN REAL TIME, PROVIDE A SHUTTERIN CASE OF OVERHEATING, AND ALLOW OPTIMIZATION OF THE OPTICAL PROPERTIES FOR CHANGES IN THE SOLAR CONDITIONS, STARTUP, OR AGING OF THE COLLECTOR. WE PROPOSE TO FABRICATE AND CHARACTERIZE AN ELECTROCHROMIC HEAT MIRROR WITH THIN LAYER STRUCTURE [TC/EC(D[1])/TIC/EC(D[2])/TC] WHERE TC AND TIC ARE TRANSPARENT ELECTRONIC AND IONIC CONDUCTORS, RESPECTIVELY. THE ELECTROCHROMIC MATERIAL, EC, WILL BE MO O(3) DEPOSITED BY RF-SPUTTERING. THE USE OF SYMMETRICAL STRUCTURES WHERE THE THICKNESS OF THE EC FILMS, D(1) AND D(2), DIFFER BY AN ORDER OF MAGNITUDE ALLOWSTHE COMBINATION OF BOTH HIGH INFARERED REFLECTIVITY AND MINIMUM ABSORPTION IN THE VISIBLE. THE GOAL OF THE PROPOSED RESEARCH IS TO DEVELOP THE HEAT MIRROR WHICH WILL ALLOW RAPID ADJUSTMENT OF THE REFLECTIVITY EDGE OVER THE RANGE FROM 1 UM INTO THE VISIBLE WHILE STILL RETAINING A HIGH FIGURE OF MERIT FOR THE SELECTIVE SURFACE.