Solar cells from donuts and tea

posted Mar 19th 2009 12:05pm by Caleb Kraft
filed under: solar hacks

It sounds unbelievable, but it is true. You can harvest most of what you need for a simple solar cell from powdered donuts and tea. Powdered donuts have nanoparticles of titanium dioxide which is a “high band gap semi conductor”. This means that it can be used to make solar cells. The tea is simply used to dye the material so it can pick up the visible spectrum. The process is a bit too involved to be something you would just toss together in the field, but it’s cute nonetheless.

Comments [40]

tagged: donut, solar, tea, titanum

Reader Comments

Hardly practical, but very educational!

Posted at 12:59 pm on Mar 19th, 2009 by Arthur Hall

“If he thought to himself, such a machine is a virtual impossibility, then it must logically be a finite improbability. So all I have to do in order to make one is to work out exactly how improbable it is, feed that into the finite improbability generator, give it a fresh cup of really hot tea…and turn it on!” ~Douglas Adams, The Hitchiker’s Guide to the Galaxy

still very interesting
ty

Posted at 1:14 pm on Mar 19th, 2009 by tRANIS

Hey… the video doesn’t work!

Posted at 1:38 pm on Mar 19th, 2009 by Nacho

Hardly practical? The whole point of the video was showing how practical it could be. Every single piece of equipment can be found at home or at Wal-Mart. It may not have the same kind of power output of a PV or amorphous silicon cell but the idea of insanely cheap and accessible parts being turned into energy-saving devices has limitless practical applications.

Posted at 1:41 pm on Mar 19th, 2009 by Patrick

@patrick
please point to the conductive glass I can buy at walmart so I too may harness the awful power of the sun.

Posted at 1:46 pm on Mar 19th, 2009 by loupgarou21

I can picture the headlines now… “Powdered donut prices soar”, “Donut shortage causing grief to millions”, “Cops on lookout for heavily armed donut thieves”

Posted at 2:30 pm on Mar 19th, 2009 by Relaxalittle

man, there is titanium dioxide in sun blocker also, so it must be checked out.

Posted at 2:31 pm on Mar 19th, 2009 by rikiardo

You can buy a tin of titanium dioxide paint tint from some hardware stores.

Posted at 2:33 pm on Mar 19th, 2009 by BigD145

interesting.

did he remind anyone else of ashton kutcher?

Posted at 2:40 pm on Mar 19th, 2009 by djrussell

Last I heard, the world’s supply of indium is running low…

Posted at 3:33 pm on Mar 19th, 2009 by Tim

Great video. Wish I had an ammeter with the “lightning” setting.

Posted at 3:38 pm on Mar 19th, 2009 by tony

i’d rather use hair dye, indigo, henna, or some other dye than support starbucks. it’d also be a better idea to use black dye, i assume

Posted at 3:48 pm on Mar 19th, 2009 by cyanide

When I first started the video, my first reaction was a groan of displeasure at the style… which changed very quickly to delight.

It turns out that actual, factual, interesting scientific content makes that self-depreciating style of video palatable, even pleasurable.

English: It was good, me happy.

Posted at 3:55 pm on Mar 19th, 2009 by Will

I, too, would prefer a website with instructions and schematics and pictures and stuff instead of a youtube video, but the important thing is that random things connected to electricity can become semiconductors. This discovery happens again and again. The message to the experimenter is: “hook up random crap to electricity and see what happens,” rather than using your mental and physical energy to complain about other people’s experiments on a forum.

Posted at 4:20 pm on Mar 19th, 2009 by sol

@sol

My dad died because he hooked up random crap to electricity. Except it was his crap, at 80,000 watts. While he was crapping it. Oh god don’t make me remember.

Posted at 4:48 pm on Mar 19th, 2009 by hum4n

@sol
unusual, unexpected or miscellaneous != random

But yeah, it’s true. The unlikeliest of substances can contain or become semiconductors. I’d love it if, when a room temperature superconductor is discovered, it turns out to be something just as outwardly ordinary.

Posted at 4:49 pm on Mar 19th, 2009 by cynic

I’ve seen a metallic blue spray paint from a hardware store used on a peace of acrylic to produce a 2″ x 2″ 0.48V cell.

There use to be people selling the instructions on the net too, but it all disappeared.

I’m pretty sure it was the titanium dioxide in the paint. I think they used small wire and aluminum foil with silicon glue to wire it somehow.

I wouldn’t bend the context of practicality on this method though; you can’t actually find some of that stuff at department stores etc.. Practical would be grocery store, gas station, or local hardware store.

Posted at 5:13 pm on Mar 19th, 2009 by TJHooker

Step by step instructions:

http://www.solideas.com/solrcell/cellkit.html

Posted at 6:36 pm on Mar 19th, 2009 by bueller

mmmmm… donuts…
I have to try this
@bueller thanks for the link

Posted at 7:21 pm on Mar 19th, 2009 by Wraith

By strange coincidence I just bought about 10 packages of those doughnuts. Now I know what to do with them I guess.

Posted at 8:32 pm on Mar 19th, 2009 by ross

Guy in video here -

Can’t believe I made Hack A Day! So glad some people appreciated my peculiar sense of humour and my science. And GROAN @ the person above who mentioned ashton kutcher…

I submitted a version of this video to an ACS contest, and could use all the support I can get:
tinyurl.com/blake-acsnano

Posted at 8:49 pm on Mar 19th, 2009 by Blake Farrow

Titanium dioxide is used in other foodstuffs too, like smarties for the white inner coating over the chocolate.

Posted at 9:09 pm on Mar 19th, 2009 by Roger

@roger or possible roger detractors:

Smarties do in fact have chocolate in them. Not those nauseating discs of confectioners sugar and ascorbic acid sold as candy stateside, but rather the delicious better-than-an-m&m candy coated chocolate sold in more civilized parts of the world…

Posted at 9:30 pm on Mar 19th, 2009 by dubmuffin

the future of solar energy begins with breakfast

Posted at 5:48 am on Mar 20th, 2009 by atomic

YASHAD (Yet Another Stolen HackADay)

This method has been around since (at least!) May of 2006 when I found it here:
http://www.solideas.com/solrcell/english.html

Does no one cite sources anymore?

Posted at 6:48 am on Mar 20th, 2009 by jason

that looks like the kitchen from fight club…

Posted at 7:50 am on Mar 20th, 2009 by zombie_funk

Really, you aren’t using the donuts at all… Just the powdered sugar. Presumably, any kind of tea- similar to that one, would also work- So you really go from false advertising, to free advertising for a company like Starbucks. Nice science fair project, schmuck.

Posted at 9:29 am on Mar 20th, 2009 by Eric

Needless to say, you can’t EAT solar cells!

Posted at 9:31 am on Mar 20th, 2009 by Eric

your all a bunch a cynics. sheesh. Good job on the educational video dude!

Posted at 9:53 am on Mar 20th, 2009 by danman

Anyone else notice the fake lens flare towards the end? I call shenanigans!

Posted at 10:50 am on Mar 20th, 2009 by Cheese

too all the cynics:

this is a very well known method for making solar cells, published as far back as the 70s by Graetzel’s group out of switzerland. The whole donuts and tea thing is just a way of making it a bit more catchy and interesting to the masses. And anything that makes science more catchy and interesting is good, amirite?

fake lens flare was all me… I didn’t think it was very clear that it was a sunny window, so I added it there for kicks. the lens flare button was right beside the lightning one, had to use it. We have much more quantitative results done in solar simulators using much more reliable equipment. An open window is just easier to come by.

Posted at 11:21 am on Mar 20th, 2009 by Blake Farrow

ah ha! so it -was- fake lens flare. id love to see a demonstration of this in person some day, though i’m not sure where one acquires ‘conductive glass’

Posted at 3:20 pm on Mar 20th, 2009 by Cheese

conductive glass… I’m thinking all glass must be conductive, at least to some extent. My father tells me a story of how his mother was working in the kitchen when lightning came through the glass window, circled the kitchen and left via another glass window. I know it sounds weird but there ya go.

Posted at 1:06 am on Mar 21st, 2009 by random thoughts

@random thoughts : glass is used as an insulator in various high voltage stuff, so I would say that conductive glass is not your common type of glass. What your father witnessed was probably ball lightning, a not-so-rare occurrence of lightning. (5% of US population seems to have witnessed one)

Posted at 6:34 am on Mar 21st, 2009 by Iv

Photocopier/high speed scanners tended to use a slightly to moderately conductive coated platen glass if they had ADF or RADF document handlers. As the static charge was wreaking havoc of several sorts. Paper showed “stiction” to the glass and dust was electrostatic field drawn to the glass. Scrapped platen glasses thus could be a not unobtanium source for conductive glass. Same with some “Low E” energy efficient window glasses. Metal Vapor Deposition is edgy for home tech folks but Mirror Silvering is not totally impossible if the chemical hazards are respected.

Posted at 10:30 pm on Mar 21st, 2009 by Oren Beck

hey eric, you’re a douche.

see, i can state the obvious, too.

Posted at 7:14 pm on Mar 22nd, 2009 by anon

http://www.unitednuclear.com/chem.htm

They sell Titanium Dioxide for relatively cheap…FYI.

Posted at 9:52 pm on Mar 22nd, 2009 by Ian

This is a useful article though… And you know, John Rogers, professor of science and materials engineering at the University of Illinois and his team have created a new method to produce flexible solar cells, transparent and extremely thin.

Posted at 2:06 am on Jun 7th, 2009 by Solar Cells

This video is very educated. It’s always interesting to find out how he made that. I need to stop myself from trying to make this thing. What I’m really interesting is how to power air conditioner unit with solar energy? I know it power car, but why not air conditioner unit or my hot water.

Posted at 9:08 pm on Aug 30th, 2009 by Solar Energy Guy

That is really crazy. The video was very informative. I found a great guide that describes how you can make your own panels here… it has videos too

http://www.squidoo.com/Do_it_yourself_solar_panels

Posted at 6:15 pm on Oct 7th, 2009 by Andrew