MIT researchers invented new and improved thin film solar cells that present 50% more efficiency, while being much more cheap than classic solar cells. Their price is due to using less silicon than conventional solar cells.
The researchers used computer simulations and experimented in their labs on 2 micron thick silicon wafers. They used new materials for the front and back coatings. The aim is to keep the light as long as possible inside the cell’s walls, to increase its efficiency (they say their innovation increased the energy per photon with about 50%), by increasing the probability of absorption and transformation to electricity.
This time the researchers used anti-reflective coatings on the front, to maximize the quantity of absorbed light, and diffraction gratings on the back, to reduce the back reflection. Normal solar cells use a layer of aluminum to reflect the light, but a great part of it is lost by going back to the origin medium.
All of these innovations are said to lower the thin film solar cells’ cost down to the grid’s, but it will take another estimated three years to reach the consumer market in a cost-efficient manner.