Thin Film Solar Cells, inspired by azimov
 

There has been recent discussion about solar powered zipzaps. I'm glad people brought back the idea and that Azimov got to show off his work a bit more.

Researching, I found a picture of a plastic thin film solar cell that someone was trying to use, not sure if it was azimov. Following some of the provided links in the thread, I stumbled on a store to get these:

http://www.solar-world.com/images/flex.jpg

http://www.solar-world.com/PowerFilm.htm

I recognized that layout of solar cells right away. Doing a little research, I found that they were indeed PowerFilm cells. My specification is semiconductors in EE at Iowa State. There is a company close to Ames (where Iowa State is) called Iowa Thin Film, the maker of PowerFilm cells.

My main professor that I have interacted with and researched for does research in thin films. I've actually helped to run tests to help Iowa Thin Film. I considered trying to work there once upon a time. They have a great system. While not super efficient, their cells can be mass produced and are very practical.

Their cells are made using plasma enhanced chemical vapor depostion, basically using Silane (SiH4) in a plasma reactor that isolates the silicon and deposits it on a film.

Most of there cells are around the two micron area for thickness or .0001 cm. The Silicon is deposited on a conductive plastic called polyimide. They have a giant roll on one side that rolls through the plasma reactor and winds up done on the other side.

Of course it's a little more complicated in that they also have to deposit aluminum fingers on the top of the solar cells.

They really are super flexible and the military loves them. They've integrated them into tents.

http://www.powerfilmsolar.com/produc...ents/index.htm

Also used for fold up battery chargers for soldiers to carry with them on longer missions. A secret ops reconisance soldier would typically take around 12-24 batteries with them. When they were gone he was done. Now he can carry a fold up battery charger and rechargable batteries and go as long as he wants.

http://www.powerfilmsolar.com/produc...tary/index.htm

It really is some cool stuff, and I'm glad it's getting used. Thin films might be the future of the solar industry since it uses less than 1/100 the silicon of typical crystalline silicon solar cells.

Sorry, solar power is a soft spot with me, I hope at least someone found this interesting. I think azimov will.

Yes, very interesting. I've used these thin film solar cells on quite a few projects. They didn't work as well as I wanted on Solar Zip #2, but I've used them with success on kinetic sculptures. Here's one.

Dang, that thing looks crazy. I see a lot of capacitors. How much free time do you have?

LOL, that depends on your definition. Other than the time I spend on this forum, and an occasional game of WoW, all my time is spent working on projects or attending classes. I'm currently wrapping up the sound on an animated short, so I have a little time to blow on microRC projects and posting here before I dive into my next production.
The sculpture shown above is an example of another of my obsessions, solar powered robotics and kinetic sculpture. I sell them here and there but, am concentrating more on animation ATM. Here's a pic of a real robot I built. It's fairly small and would roughly fit inside of a baseball. The sculpture posted previously moves it's head and blinks LEDs, but doesn't sense or react to it's enviroment. This bot can sense light lvls and react to obstacles. It can also change behavior depending on light lvls. It slows down in less light and waggles back and forth conserving energy until it finds a better source of light.

Have you ever ordered a "grab bag" of solar cells, like that site that was posted? They say there were broken ones from manufacturing and there are some 40 pieces for relatively cheap. I have no idea what to expect with those... Making an array would be difficult to try to match currents from each one. I considered getting one to see what it inculded and how big of pieces.

No, I've never ordered one of those grab bags. I've been tempted to as well, but was afraid of what I might get.