Civil Engineering Reference
In-Depth Information
Fig. 7 Structural models for WO
6
octahedra in W oxide films made by evaporation onto
substrates at the shown temperatures (RT denotes room temperature). Arrows in the x and
y directions are 2 nm long. After Nanba and Yasui (
1989
)
Fig. 8 Schematic diagram
showing thin-film
nanostructures for different
pressures in the sputter
plasma and for different
substrate temperatures. The
material's melting
temperature is denoted s
m
.
From Thornton (
1974
)
is desirable for electrochromic applications. It is of interest to notice in this context
that the deposition may involve molecular species, and trimeric W
3
O
9
molecules
are well known to form during evaporation (Maleknia et al.
1991
), while a pre-
ponderance of (W
6
O
19
)
2-
(known as ''Lindqvist anions'') may be present in
aqueous solutions (Lang et al.
2012
) used for liquid-phase thin-film deposition.
2.3 Optical Absorption Mechanisms
The reason for the variable optical absorption in electrochromic materials has been
discussed extensively and is a complicated issue for several reasons. First of all, the
oxides are often poorly defined regarding crystallinity, and they can incorporate
