Highest Efficiency Light to Charge Converter

Aside from common silicon solar cells, any options with higher efficiency will be quite expensive. Is there any possibility that you can "duty cycle" your application with capacitive energy storage to require less average power?

Certainly, common knowledge includes the fact that silicon is most efficient around 980 nM wavelength. Can you use an IR source?

Good luck in your quest.

Bernie Katz

Dear Berniek

I need to find way to convert light into 1W DC usable power in one cubic inch or less space. Some of the light to charge converters may be able to do that. I can pump high power at the input to say 3W, then can I get 1W at the converter? I am also worried about wastage of power.

Dear Shyam:

If the light falls on one face of a one cubic inch cube, the area will be one square inch, or 1/1600 of a square meter. At the equator, solar flux is about 1 Kw/square meter. So for 1/1600 of that value or one square inch, the solar flux would be .625 watts. That would be the light power you would need for a one square inch receptor assuming 100% efficiency, to generate 0.625 watts. We can see immediiately that the light (or IR) flux needed would be in excess of the solar flux, again at 100% conversion efficiency. If we figure 18% efficiency for solar cells at 980 nM, the IR power you would need would be .625/.18 = 3.47W, all concentrated on one square inch .

However, 18% efficiency, even at 980 nm might be pushing the present envelope for silicon cell efficiency.

I've faced problems of this nature before, and have dealt with it by operating the equipment at low duty cycle. If you need to operate for several seconds each 20 seconds or so, you can use supercapacitors for energy storage tasks.

Hope this helps.

Bernie Katz