Solar cells are becoming cheaper to make, which is why we are seeing a lot of renewed interest in them with many solar farms cropping up all over the world. However, although the cell technology has been getting cheaper, it’s has remained rather low. From initial 12% conversion rates, the new technology available on the market has managed to improve somewhat to a 14% to18% efficiency rate… ie 18% of the sun’s energy is converted to electric energy. This due to various factors, but the main one being because the materials used for this are only able to absorb a certain part of the light energy which make up the sun’s rays. The sun’s light is made up for a large spectrum such as the different colours that come from a rainbow, the UV light, the infra-red light which we feel as heat and so on.
Furthermore, this technology is only able to convert a theoretical maximum of 33% of the total solar energy. So even if this technology is improved in the future, it will never be able to achieve as good a conversion rate as other technologies which use more expensive materials and manufacturing techniques such as solar cells on satellites.
Now all this may be about to change as reported by gizmag. The limitations of our current commercial grade solar cells are mainly due to the fact that it cannot absorb either high energy light or low energy light, it is only suited for a limited fraction of the light that makes up the spectrum of sun light. New research suggest that a new technique could see a layer of chemicals interacting with sun light before it reaches the solar cells, whereby these chemicals would convert the low energy light present in sun light into a light that is better suited to be absorbed by the solar cell.
Imagine, for simplicity, that sun light is made up of 3 type of energy light, red light (low energy), yellow (medium energy) and blue light (high energy). Now, in this case, our solar cell can only absorb the yellow light, the red and blue being lost. The new chemical filter being proposed would absorb the red light and convert it into yellow light, thus the solar cell would get an extra dose of yellow, while the blue light would still be lost.
If this technology makes it to the manufacturing process, we could get solar panels that would convert up to 40% of solar energy.