Solid state electrochromic 'smart' windows. Final report, May 1, 1987-August 31, 1990.

摘要

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 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.