Switchable glazing technology for eco-efficient construction - Nanotechnology in Eco-efficient Construction - page 246

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60

50

40

30

20

10

0 500 1000

Time (s)

1500 2000

11.3 Mid-luminous transmittance vs. time during repeated colouring
and bleaching of an electrochromic foil device of the type illustrated
in Fig. 11.2.

50

40

30

20

10

￿ ￿ ￿ ￿ ￿ ￿

0 0

50 100 150

Time (s)

200 250 300

11.4 Mid-luminous transmittance vs. time for repeated colouring and
bleaching of two superimposed electrochromic foils of the kind
described in Fig. 11.2. From Granqvist (2008).

11.3 Thermochromics: materials and devices

Thermochromism is well known in a number of metal oxides and sulphides
(Lampert and Granqvist, 1990; Smith and Granqvist, 2010). Vanadium
dioxide, VO 2 , stands out as the most interesting material with regard to
eco-effi cient technologies, and its thermochromism has been known for