New silicon treatment promises better solar cell production

Engineers at Michigan Technological University have found that applying an atomic level coating to "black silicon" dramatically reduces the production costs of solar cells. Black silicon is the name given to the material when it has been treated by a dry etching process to create a surface texture resembling a forest of nanoscale needles.

Conventionally, solar cells appear blue because of a surface treatment designed to improve the amount of light they absorb. This treatment is applied to both perfect silicon crystal cells and multi-crystalline silicon which is slightly cheaper. However, the reflection of light, even with the wavelength shift, indicates that not all the light is captured by the cells. Joshua Pearce, professor of materials science and electrical engineering at MTU, is investigating black silicon, whose surface captures much more light and therefore appears to not reflect at all, and attempting to discover whether it could be a feasible large-scale replacement for the current types of surface-treated silicon.