Michael Graetzel of Swiss Federal Institute of Technology in Lausanne achieved a break though in 1991. That was when he invented dye-sensitized solar cells that performed better in dim light, and cost less than standard semiconductors. The modern equivalent, diffused light solar cells may power our TV remotes soon, without a conventional battery in sight.
Operating Principles of Diffused Light Solar Cells
Dye-sensitized solar cells (DSSC’s) are only able to convert 14% of solar to electricity, because the energy enters too fast. However, Graetzel discovered they had almost twice that capacity in low-intensity indoor light, that they could cope with better. This is the opposite trend to conventional photovoltaic cells. Why is this so?
HOW SOLAR CELLS DO THEIR WORK
Sunlight in conventional solar cells raises energy levels in silicon atoms, so they enter a positively-charged electrode, and create electricity. The gaps they leave behind travel to the negatively charged electrode, according to Science. There they accept electrons from the external circuit, re-balancing the charges and allowing the process to continue.
THE DYE-SENSITIZED SOLAR CELL DIFFERENCE
DSSC’s also have electrodes collecting negative and positive charges. However, they use a different separator, typically titanium dioxide particles, compared to photovoltaics’ pure silicon. But titanium dioxide is a pure light absorber, and so researchers coat this with organic dye molecules that are exceptional light absorbers.
Low Light Solar Cells Entering the Market
We’ve heard tell of a variation on the theme of diffused light solar cells, preparing to enter the market quite soon. The developer claims this is three-times more efficient than the industry standard, and is set to ‘sweep away’ battery remotes in dim places. We shall watch this space with interest, and see how this pans out.
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