By Solar Spark, this activity explores the relationship between light scattering and colour through anodising. This is the electrochemical process used to thicken the protective oxide layer found on several metals. Aluminium is the most common metal treated in this way, but others, including titanium can also be anodised.
Thick layers of titanium oxide can be achieved electrochemically and the different colours produced are often used in art, jewellery and dental implants. Nanocrystalline titanium dioxide (TiO2) is used in dye-sensitised solar cells where it acts as the semiconductor on one of the electrodes. Titanium dioxide in this form is white and does not absorb visible light so light-absorbing coloured dyes are bonded to it to enable their use in solar cells.
This activity can be used to illustrate:
• oxidation states
HEALTH and SAFETY
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