December 15, 2008
Leaf-shaped material harvests
Form titanium dioxide into the exact
structure of a leaf and you can make the semiconductor absorb more
visible light than its bulk form. This could boost solar cells and
water-splitting hydrogen generators.
The process replaces a leaf's biological material with titanium
dioxide, retaining the structure of the leaf down to the nanoscale.
Think fossilization rather than gilding a lily.
Titanium dioxide is inexpensive but it mostly absorbs ultraviolet
light, and ultraviolet light is only a small portion of the solar
spectrum. The leaf shaping more than doubles the amount of visible
light the material absorbs.
Titanium dioxide is used in dye sensitized solar cells and
as a photocatalyst for extracting hydrogen from water using sunlight.
Light-Harvesting and Photocatalytic Properties in Morph-TiO2 from
Advanced Functional Materials, published online December 12,
Key Lab of Metal Matrix Composite
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