Let’s call them ‘organic solar collectors’, for want of a better word. But it is exactly what this new development in glass technology does. We get it directly and indirectly everyday, but solar power in actuality is very expensive. Now, a new technology promises to turn your windows into veritable solar panels or acting as solar collectors improve the efficiency of existing solar cells, reducing the cost of solar power.
Solar panels inherently have two major pitfalls – cost and performance. Some say that solar power is just a problem waiting for an elegant solution. Is this breakthrough M.I.T (Massachusetts Institute of Technology) experiment the solution?
Engineers at M.I.T have developed an organic dye which coated onto an ordinary sheet of glass, traps light inside the glass and allows it to be channeled to photovoltaic cells placed along the edges of the sheet. In simple terms, a window is turned into a solar concentrator, by painting it with a mix of organic dyes and setting small solar cells around the edges. The collector would be able to harness 20% of the incident light and turn it into electricity at a fraction of the cost of a photovoltaic cell. This could also substantially reduce the cost of generating solar power, because the expensive photovoltaic cells need only be mounted around the edge of the panels to act like a siphon for all the incident energy.
Traditional solar collectors use mobile mirrors to track the sun and concentrate the rays onto a solar cell, but the moving parts of a mobile mirror are expensive and require frequent maintenance. This is where the cost becomes a major barrier for widespread solar adoption.
The crux of this new solution lies in the properties of the unique dye. Using specific combination of organic dyes (each with its own absorbing wavelength) allowed the molecules to absorb sunlight over a wide range of visible wavelengths and then emit light at a longer wavelength. As the dye matrix absorbs most of the wavelengths, little is lost and efficiency is thus gained.
The organic solar concentrator (OSC) developed by the MIT team has a conversion efficiency of 6.8 per cent. This effectively means that 6.8 per cent of the energy collected by the OSC is turned into electricity. This is lower than silicon or thin film panels though, which have efficiencies of 14 and 10 per cent respectively. However, because expensive silicon-based cells are only a small part of the OSC, the cost ‘shavings’ allow for cheaper electricity.
The direct advantage of a dye based approach also lies in the fact that older panels can be retro-fitted. The system is simple to manufacture, so the development team expects it to be on the market within three years.
Of course the dye based approach though an immediately cheaper solution has its own subset of disadvantages. The dye’s life span is expectedly only three months. Again, as observers have pointed out that the estimated efficiency is still not good enough for commercial applications.
Maybe not. But the start seems promising enough and optimistically we should get there one day.
Source: New Scientist