A team of chemists at the University of California, Davis believe that the future of solar technology may lie in cells made from a film of tiny silver nitrate fractal trees. The research team, led by Professor Frank Osterloh, believes that by harnessing the conductive power of these fractal trees, they might create “better, more efficient solar cells” than the silicon-based photovoltaic panels currently available.
image © flickr user twicepix
The incredible, intricate structure of silver nitrate fractals forms when the silver salt is applied to flourine doped tin oxide. The resulting electrochecmical reduction causes the silver nitrate to grow into a tiny tree like structure, with central “branches” of silver nitrate less than 1/50th the width of a human hair supporting ever smaller branches. The resulting sheet of miniscule silver fractals is then coated with a light absorbing polymer to harness its solar potential.
UC Davis explains that “When light particles (photons) hit the polymer coat, they produce short-lived electrons and holes (positive charges) in the polymer. The positively charged holes are collected through the silver branches, while the electrons move to the counterelectrode to create an electrical potential.”
Osterloh suggested that comparisons between the new technology and nature go beyond the tree-like structure of the fractals, stating that the nano-sized branches of silver spread out to form a large light-absorbing surface area in much the same way that the canopy of a tree extends outwards to gather more light into its leaves.
The researchers hope that solar cells crafted from a film of silver fractals could be significantly more efficient than current photovoltaic solar cells. Commercially available solar panels typically only convert between 12-20% of available energy into electricity. While we have not seen any specific efficiency goals from UC Davis, we remain very curious as to how their prototypes will perform over their photovoltaic kin. If, as Osterloh hopes, they can make significant strides in the efficiency level of solar technology, solar providers may find themselves even better placed to compete against the fossil-fuel energy market.
Working with a 100,000 grant from Research Corporation for Scientific Advancement, Osterloh’s team at UC Davis will oversee the construction of the prototype Silver Fractal Solar cells.
Lead image © Frank Osterloh/UC Davis