By Peter Weiss
Researchers in Germany have modified standard solar cell designs so that they can be made from cheaper materials. That could be important, because price has long been a major obstacle to wider use of photovoltaics.
Typically in commercial solar cells, photons from the sun jolt electrons loose from chemical bonds in a layer of silicon several hundred micrometers thick. Dislodged electrons escape the silicon layer into an adjacent substance that lets them flow freely.
To ensure that liberated electrons don’t get trapped by defects within the silicon’s crystalline structure, manufacturers deposit the material with as few defects as possible. That precision in manufacturing adds to the cell’s cost.