For most of human history we have taken inspiration from nature when developing technologies and one of natures most intricate designs comes in the form of diatoms. These aqueous organisms grow a three dimensional porous silica shell around them for protection. The organisms themselves being photosynthetic it was thought that silica shell could not inhibit light capture, otherwise the organism would perish, but may actually enhance it via trapping and scattering effects. For solar applications silica is unsuitable as it is an insulator, meaning the shells had to be coated with a more solar applicable material. Titania was selected as it is a standard material for dye sensitised solar cells (DSSC’s). When these new structure were then incorporated into the DSSC design it resulted in enhanced efficiencies. This is one of the many applications of these abundant, easily functional three dimensional porous structures that nature has already constructed for us to utilise.
SEM pristine diatom shells TEM TiO2 coated diatom shells
By Jeremiah Toster, PostDoc with Professor David Lewis