Nanotechnology “Solar Ink” Increases Photovoltaic Efficiency

A nanowire manufacturing technique promises to improve solar cell efficiency at a low cost.

Photovoltaic panels enhanced with nanowires can be up to 25% more efficient than traditional PV panels. While the concept was demonstrated several years ago, one obstacle remained: producing these nanowires and adding them to PV panels at a reasonable cost. Solar upstart Sol Voltaics, founded by nanotechnology expert Lars Samuelson, has developed a nanowire production process that promises to make nanowire PV cells cost effective. Rather than growing nanowires on a silicon substrate, a process that’s both slow and costly, Sol Voltaics uses a process called Aerotaxy™, which grows the nanowires in a solution of active materials and gases. The result is a material that Sol Voltaics calls SolInk, which can be stored and later applied to the surface of PV panels.

The active materials in SolInk are gold and Gallium-Arsenide GaAs. Although both of the ingredients are expensive, they’re used in such minute quantities – less than a gram per solar panel – that the overall cost is very low. Vaporized gold acts as a catalyst, allowing P-type and N-type GaAs molecules to bond to it. PN junctions are formed, turning the nanowires into miniature high-performance photovoltaic cells. The process grows nanowires in fractions of a second, at least 20 times faster than traditional methods. This video shows the Aerotaxy™ process:

Image and video: Sol Voltaics

SolInk can be placed on top of existing solar panels, creating a multijunction PV panel. Single-layer PV panels are “tuned” to one wavelength of light, resulting in low efficiencies. Multijunction panels use several layers, each tuned to a particular wavelength. SolInk placed at the surface captures light with short wavelengths. Longer wavelengths of light pass through that surface and are absorbed by the layer below. Sol Voltaics plans to sell SolInk to PV manufacturers. Dave Epstein, Sol Voltaics CEO, estimates that SolInk will add less than 3% to the cost of manufacturing a solar panel, while increasing its efficiency by up to 25%. Now that’s a bright idea!