Thin and ultra-thin films by solution chemistry
Gunnar Westin
1
, Kjell Jansson
2
, Koroush Lashgari
1
, Annika, Pohl
1
, Åsa Ekstrand
1
,
Michael Leideborg
1
, Victoria Coleman
1
, Sarmad N. Katea
1
1
Department of Chemistry-Ångström, Ångström Laboratory,
Uppsala University, 75121 Uppsala, Sweden
2
Department of Materials and Environmental Chemistry, Arrhenius Laboratory,
Stockholm University, 10691 Stockholm, Sweden
E-mail
For development of devices for renewable energy conversion and storage there is an ever
increased demand for complex composition and structure multifunctional materials.
In solar cells and water splitting devices the design requirements are down to a few
nanometers for utilization of quantum size effects and modification band band-bending near
the surface or increased corrosion resistance. This put great demands on the precision of the
preparation routes. At the same time the process and materials have to be of very cost for any
societal impact to occur. Such tough demands can for most cases only be met by solution
based routes.
Here we describe solution based processing routes to doped and non-doped oxide, metal
and metal - oxide nano-composites in various shapes with an emphasis on thin- and ultra-thin
coatings down to 1-5 nm thickness on flat and complex substrate structures. The systems
involve doped and non-doped semi-conductor oxides, spinels and perovskites. The steps
taking the precursors in solution into the target materials have been investigated in detail with
a wide range of experimental techniques including; SEM, TEM, XRD, TGA, DSC/DTA,
XPS, IR-, Raman and UV-Vis-NIR spectroscopy. Although the processing is central in this
discussion, examples will be given where the processes have been used in large scale, such as
record efficient solar thermal absorber of Ni-Al
2
O
3
graded nano-composite films prepared in
50 m roll-to-roll processing showing the scalability of the processes.
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