Solar cells are at a prime these days. Researchers all over the world are working towards improving the efficiency, size and cost factor of the technology. This is because it is a known fact that traditional sources of energy are fast depleting and the time is not far when the world will heavily rely on solar energy. The latest innovation comes from the University of Oslo. The researchers at the University have reportedly developed silicon solar cells that are twenty times thinner than the original solar cells.
This innovation basically means that solar cells can now be produced using 95 per cent less silicon. This will considerably reduce the production costs, thereby increasing profits and reducing the cost of solar power installations.
According to an Extreme Tech report, “Standard, commercial photovoltaic solar cells are fashioned out of 200-micrometer-thick (0.2mm) wafers of silicon, which are sliced from a large block of silicon. This equates to around five grams of silicon per watt of solar power, and also a lot of wastage — roughly half of the silicon block is turned into sawdust by the slicing process. With solar cells approaching 50 cents per watt (down from a few dollars per watt a few years ago), something needs to change.”
The report further talks about how reducing the thickness of solar cells definitely is an achievement from a commercial point of view but it does give rise to issues. For example, as the wafer gets thinner, more light passes straight through the silicon, dramatically reducing the amount of electricity produced by the photovoltaic effect. This is due to wavelengths: Blue light, which has a short wavelength (450nm), can be captured by a very thin wafer of silicon — but red light, with a longer wavelength (750nm), can only be captured by thicker slabs of silicon. This is part of the reason that current solar cells use silicon wafers that are around 200 micrometers — and also why they’re mirrored, which doubles the effective thickness, allowing them to capture more of the visible spectrum, the report added.
Basically, these researchers have managed to trap the longer wavelengths, even when the silicon wafers were just 10 micrometers thick. This could happen by using microbeads that are very small plastic spheres, uniform in size. They create an almost perfect periodic pattern on the silicon. These beads force the sunlight to “move sideways,” increasing the apparent thickness of the silicon by 25 times.