Grey, brown and blue coloring sol–gel electrochromic devices

Abstract

Pure and doped niobium oxide (Nb 2 O 5) layers are electrochromic (EC) materials which change their color by insertion of Li + ions from transparent to brown, grey or blue depending on the crystallinity of the layer. EC devices with the configuration K glass/EC layer/composite electrolyte/ion storage (IS) layer/K glass, were produced using different Nb 2 O 5 EC layers, a (CeO 2) x (TiO 2) 1Àx (x 0.45) IS layer and an inorganic organic composite electrolyte to which a small amount of water (up to 3 wt.%) was added. The grey coloring all solid state sol gel devices fabricated with Nb 2 O 5 : Mo coatings show a high reversible coloration (DOD 0.3) and a long term stability of more than 55 000 switching cycles. Large area EC devices (30 Â 40 cm) show a transmittance change between 60% and 25% at 550 nm after galvanostatic coloration and bleaching for 3 min and a coloration efficiency of 27 cm 2 /C. The results obtained with blue and brown coloring Nb 2 O 5 EC layers and a comparison with blue coloring WO 3 layers are also presented.

Solid-state electrochromic devices with Nb2O5:Mo thin film and gelatin-based electrolyte

“…This value is stable up to 10 000 cycles and then starts to decrease very slowly to reach a value of 14% after 25 000 cycles. However, the variation of the transmittance of Nb 2 O 5 :Mo thin film at λ = 550 nm in1 M LiClO 4 /PC electrolyte was 63% after 3500 cycles [23].…”

Properties, requirements and possibilities of smart windows for dynamic daylight and solar energy control in buildings: A state-of-the-art review

“…The interest in niobium pentoxide Nb 2 O 5 has increased in the last decade because of its promising electrochromic properties (Maček et al 1997, Pehlivan et al 2003Pehlivan et al 2005;Heusing et al 2006;Mujawar et al 2006Mujawar et al , 2007Romero et al 2009 …”

Structural investigation of ormolytes for EC devices: IR spectroscopic characterization and relation between viscoelastic properties, conductivity and optical modulation

“…The PEOCSbased electrolytes were applied between optically active WO 3 and counter NiO 1 À x -PANI electrodes and pressed together. Since assembling of EC devices at atmospheric conditions has not yet been entirely abandoned by producers, the studies of functioning of so-manufactured EC devices remains a matter of debate [2,27,28], especially regarding their stability response. The in situ UV-visible absorbance spectroelectrochemical measurements of the assembled EC devices were made after 24 h using HP8453 diode array spectrophotometer and an Autolab PGSTAT302N potentiostat-galvanostat.…”