Three‐Mode Modulation Electrochromic Device with High Energy Efficiency for Windows of Buildings Located in Continental Climatic Regions. (3rd December 2018)

• Record Type: Journal Article
• Authors: Cardoso, Marita A.; Pereira, Rui F. P.; Pereira, Sónia; Gonçalves, Helena; Silva, Maria M.; Carlos, Luís D.; Nunes, Sílvia C.; Fortunato, Elvira; Ferreira, Rute A. S.; Rego, Rosa; de Zea Bermudez, Verónica
• Is Part Of: Advanced sustainable systems. Volume 3:Number 3(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-12-03
• Subjects: di‐ureasil hybrid -- energy‐efficient smart windows for buildings -- amorphous indium zinc oxide -- N‐butylimidazolium trifluoromethanesulfonate -- visible‐ and NIR‐controlled electrochromic devices; Sustainable living -- Periodicals; Sustainability -- Periodicals; Green technology -- Periodicals; Periodicals; 628
• DOI: 10.1002/adsu.201800115
• Languages: English
• ISSNs: 2366-7486

Abstract

Abstract: A sustainable use of energy in buildings demands energy‐efficient windows. A new design concept for electrochromic (EC) smart windows, easy to implement at the industrial level, is introduced here. It enables simultaneous control of visible and near‐infrared (NIR) solar radiation, thus contributing to reduce heating and cooling loads especially in buildings located in areas experiencing wide daily temperature ranges. The EC device comprises amorphous indium zinc oxide, a conducting oxide transparent in the visible and NIR spectral regions, as nonactive layer, and a sol–gel protonic ionic liquid‐doped di‐ureasil electrolyte displaying high transparency and proton conductivity. The device offers three voltage‐operated modes: bright hot (+3.0 V: transmittances of 70/83% at 555/1000 nm), semi‐bright warm (−2.0 V: transmittances of 37/35% at 555/1000 nm), and dark cold (−2.5 V: transmittances of 6/4% at 555/1000 nm). Its main figures of merit are: high switching efficiency (transmittance variations of 64/79% at 555/1000 nm), high optical density modulation (1.1/1.3 at 555/1000 nm), high optical contrast ratio in the visible region (lightness variation of ≈43), good cycling stability, and unprecedented coloration efficiency (−12538/−14818 cm 2 C −1 and +2901/+3428 cm 2 C −1 at 555/1000 nm), outstanding optical memory (transmittance variation loss of only 24% more than 4 months after coloration), and self‐healing ability following mechanical stress. Abstract : An energy‐efficient electrochromic device enabling bright hot, semi‐bright warm, and dark cold modes through the application of +3.0 to ‐2.5 V is proposed for windows of buildings located in continental climatic regions. The system includes amorphous indium zinc oxide electrode and a protonic ionic liquid‐doped di‐ureasil–based electrolyte. The system demonstrates high coloration efficiency values, excellent optical memory, and self‐healing.