2012-04-25 Solar Cell As A LED

Quantsuff sent me a link to this article about researchers who found a new or different way to increase the efficiency of a solar cell – make it more like a LED.

I relate this experience  to demonstrate that there are technologies out there that are waiting to make a major change in how the world functions, but just haven’t yet been utilized.  Years ago I bought a small square or rectangle of a material that would allow one to test the output of an infrared LED.  It had to be ‘activated’ by exposing it to bright light, either close to a light bulb or the sunlight.  Then for a short period it would glow when an infrared LED was shone on it.

I haven’t seen this sort of thing for a long time.  But it would make sense that one could put the same chemicals into a solar photovoltaic cell, and when the wide band of sunlight hits it, the chemicals would first be activated by the visible light, then when the sunlight’s infrared hits it, it would re-emit the IR frequencies as visible light, and it would then be able to turn that light into electricity.  I may be wrong in trying to change the frequency of the light, because I am not sure how well the silicon solar cells convert IR itself into electricity, compared to visible light.  But the use of this chemical might be able to increase the efficiency of a solar cell.

In any case, in the link, the researchers have taken a new approach to the way a solar cell is designed to operate.  And this research is a step forward on the way to someday making us independent of non-renewable energy sources.

Another technique that I’ve seen is to increase the efficiency of a solar cell by gathering more sunlight and concentrating it on the cell.  The sun moves across the sky during the day, so the sunlight would go out of focus as it moves across the cell.  The solution is to move the solar cell or the whole array to point at the sun.  Ths adds to the complexity of the solar array; the array will need motors to drive it, and sensors to tell where the sun is at.

There may be a way to compromise and design a solar array that requires less or no movement, yet focuses the sun on an array that is somewhat bigger than a movable array, yet has some of the increased efficiency of a movable array.  For example, if the array had solar cells at three points of focus, and was designed to not move, it might be simple like a non-movable array, yet have higher efficiency.  And also, it’s important that it be cost effective.

I learned a few other things from this article.  They stated that the theoretical maximum efficiency of a solar cell is 33 percent.