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 approximate to 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.
keywords
OXIDE THIN-FILMS; TECHNOLOGIES
subject category
Science & Technology - Other Topics; Materials Science
authors
Cardoso, MA; Pereira, RFP; Pereira, S; Concalves, H; Silva, MM; Carlos, LD; Nunes, SC; Fortunato, E; Ferreira, RAS; Rego, R; Bermudez, VD
our authors
Luís Carlos
Full professor
Maria Rute de Amorim e Sá Ferreira André
Full professor
Marita Alves Cardoso
PhD StudentProjects
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)
Luminescent electrochromic devices incorporating organic/inorganic (bio)hybrid electrolytes (LUMECD)
acknowledgements
The authors are grateful to Fundacao para a Ciencia e a Tecnologia (FCT) and when applicable by Fundo Europeu de Desenvolvimento Regional (FEDER) under the PT2020 Partnership Agreement for financial support under contracts PEST-OE/EEI/LA0008/2013, PTDC/CTM-BPC/112774/2009, PEst-OE/SAU/UI0709/2014, UID/Multi/00709/2013,PEst-C/QUI/UI0686/2016, PEst-OE/QUI/UI0616/2014, FCOMP-01-0124-FEDER-037271, FCTUID/CTM/50011/2013, LUMECD project (POCI-01-0145-FEDER-016884 and PTDC/CTM-NAN/0956/2014), UniRCell project (SAICTPAC/0032/2015, and POCI-01-0145-FEDER-016422). M.A.C., R.F.P.P., and S.C.N. acknowledge FCT-MCTES for grants (SFRH/BD/118466/2016, SFRH/BPD/87759/2012 and LUMECD, respectively).