A team of Stanford engineers has pioneered the use of tiny spheres of nanocrystalline-silicon to increase light absorption in solar panels.

Engineers coated small balls of silica with silicon and etched away the silica center using hydrofluoric acid. This process produces lightweight spheres of silicon, which prevent light from escaping the shell after initial absorption.

Once trapped in the shell, light circulates within the structure, allowing the silicon to absorb the light as time elapses.

Three layers of nanoshells achieved an absorption rate of 75 percent. A single layer of these nanoshells was also found to absorb a broader spectrum of light than a regular layer of silicon.

The nanoshells are more cost-efficient, reducing both the amount of material used for the absorption of a unit of light and the amount of time needed to produce the shells. The nanoshells can be fabricated in just a few minutes.

The shells also absorb different light angles to a greater degree, allowing solar panels to absorb more light from the sun even when originating from different points in the sky.

The flexibility of the nanoshells further allows solar panels to be used in areas where incoming solar light angles are far from ideal.

Researchers hope to extend the use of nanoshells to sparser materials, such as Indium and Tellurium, according to Vijay Narasimhan, a current doctoral candidate working in the lab of professor of Yi Cui and a co-author of the paper published in Nature Communications.

–Judith Pelpola