Solid state electrochromic smart'' windows

Technical Report · Fri Mar 01 00:00:00 EST 1991

DOI:https://doi.org/10.2172/5946511· OSTI ID:5946511

The structure under development at EIC Laboratories consists of a multilayer stack of thin films, incorporating the two principal electrochemically active elements, the electrochromic (EC) and counter electrode (CE) layers, respectively. The EC layer changes from colorless to a state of reduced transmission on reduction while the CE layer has the opposite (complementary) behavior (or is colorless in both oxidized and reduced states). These are separated by an ion conducting electrolyte. The stack is completed with top and bottom transparent electrodes. The major achievements are as follows: (1) Tunable thermal emittance for the EC layer over a range of 0.2 to 0.8 was demonstrated, indicating the feasibility of surfaces with adjustable heat transfer properties. (2) Thin film ion conductors based on the Li{sub 2}O/B{sub 2}O{sub 3} and LiNbO{sub 3} were developed using thermal and electron beam evaporation with ionic conductivities >10{sup {minus}8} S/cm, fulfilling a major requirement for this component. (3) A variety of improved vanadium oxide-based counter electrode materials were demonstrated and patented which undergo reversible electrochemical Li insertion reactions and which increase their solar transmission on reduction. (4) Devices incorporating a laminated Li+ conducting polymer electrolyte were demonstrated with bleached state visible transmittance of >65% and colored state transmittance of <15%. These devices were tested for >10{sup 4} complete cycles. (5) An all thin film solid state device was demonstrated with a visible transmission range of 65/13%, using the component materials developed on this program. The device was tested for >3000 complete cycles without degradation. A fabrication sequence was specified which forms the basis of initial production cost estimates. (6) Window modeling studies have been used to compare the relative performance of amorphous and crystalline WO{sub 3}-based electrochromic structures. 10 refs., 17 figs., 2 tabs.

• Research Organization: EIC Labs., Inc., Norwood, MA (USA)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (USA)
• DOE Contract Number: AC03-87SF16733
• OSTI ID: 5946511
• Report Number(s): DOE/SF/16733-T1; ON: DE91011026
• Country of Publication: United States
• Language: English

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32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
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COOLING
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ENERGY MANAGEMENT SYSTEMS
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DOCUMENT TYPES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRO-OPTICAL EFFECTS
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320107* - Energy Conservation
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