Thin film solar cells from CalTech and Karlsruhe Institute of Technology have disordered nanoholes that reduce light reflection.


  • Efficient
  • Sustainable
  • Scalable


  • Commercial and industrial energy generation

UN Sustainable Development Goals Addressed

  • Goal 7: Affordable & Clean Energy

The Challenge

Thin film solar cells are lightweight and require less material to construct, making them a possible option for utility-scale solar projects. However, current thin film solar cells have high rates of light reflection, making them inefficient, as only absorbed light can be converted to energy.

Innovation Details

The high-efficiency thin film solar cells consist of hydrogenated, amorphous silicon sheets. The top layer has tiny holes of various sizes that cause light to scatter and strike the silicon base below. The base then absorbs the light to be used in solar energy generation. This design has proven to be roughly twice as efficient as typical thin film solar cells.

Biomimicry Story

Butterfly wings appear black not because of , but because they are able to absorb light with little to no reflection. This is made possible by a mesh-like surface of ridges and holes on the scales of the butterfly wing, which channels light into the scale’s interior. There, pillar-like beams of tissue scatter light until it is almost completely absorbed.