Science Buddies: "Ask an Expert"

I have looked all over for an online store where I can buy Amorphous, Single Crystal Silicon, and Polycrystalline solar cells. I can find each of these...but they're on seperate sites, and have different surface areas/ average voltage outputs. Preferably, I would like to find a site that had all three of these solar cells; since that seems impossible, though, what I need now is to find at least these three solar cells with the same voltage output. (for example, all of them could be .5 volts, or 3 volts...) The price range I'm looking at is under $30 for each cell. Any science store reccommendations? I've already exausted Edmunds and Wards Science. Thank you!

I'm not sure you can get all of them identical but you can probably work out the formula to account for the different geometries.

Have you had algebra? It's a basic practical algebra problem.

The formula is:

length*width*(constant based on material) = voltage

If you know length, width and voltage you can determine how the three materials stack up compared to each other.