Making solar cells with a kitchen microwave


May 8, 2013

Researchers at the University of Utah have discovered a method for creating solar cell material using the same microwave found in most kitchens (Photo Credit: Lee J. Siegel, University of Utah)

Researchers at the University of Utah have discovered a method for creating solar cell material using the same microwave found in most kitchens (Photo Credit: Lee J. Siegel, University of Utah)

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For most people, experiments involving a home microwave typically don't go much further than inflating a marshmallow like a balloon or reheating leftovers in plasticware – both with messy results. For metallurgists though, microwaves are sometimes employed to efficiently process metals, which is how researchers at the University of Utah found themselves using a secondhand kitchen appliance in their lab. Their resourcefulness paid off recently, when the team discovered a method for creating solar cell material with just a few basic ingredients and an old microwave.

The material is called CZTS after its components, copper, zinc, tin, and sulfur, and is known to act as a photovoltaic semiconductor, converting the sun's rays into usable electricity. Scientists have only recently begun turning to it for use in commercial-grade solar cells, since its low-cost, environmentally friendly ingredients make it a perfect fit with green energy sources. Unfortunately, CZTS has been difficult to create properly in the past and usually requires more complicated methods involving chemical suspensions.

Pierce film with fork or similar

Prashant Sarswat and Michael Free, two metallurgical engineers at the University of Utah, devised a cheaper, faster method using a microwave rescued from a student kitchen. The pair dissolved acetate salts from each metal in a solvent of oleylamine and sent that concoction straight into the microwave (presumably after wiping away the splatter from months-old spaghetti sauce). After just 8 minutes, the nanocrystals needed to form CZTS began to take shape and reached equivalent sizes after 18 minutes, which isn't bad compared to previous methods that required 45 to 90 minutes to prepare.

The resulting CZTS is suspended in an ink-like substance, which can be painted onto most surfaces or combined with other substances to build a functional solar cell. Sarswat and Free even built a small photovoltaic cell to prove their microwave-made CZTS would work. Leaving the CZTS in the microwave for specific times will also form different sizes of nanocrystals, giving the material different properties. Larger crystals absorb heat and convert it to electricity, while smaller crystals can be made to emit light at certain energy levels. The two researchers believe this could lead to LEDs that require less power.

Don't try this at home. Obviously

With cheaper, less toxic ingredients than most semiconductors combined with an easier manufacturing process, CZTS is poised to become a widespread material in a number of industries. However, the research team has warned that most people should not try to concoct CZTS in their own microwave at home since, as your mother no doubt warned you, putting metal into a microwave can be dangerous.

Sarswat and Free also learned during the course of their study that a research team at Oregon State University was developing a similar microwaving method, though their process uses different chemicals. The pair of metallurgists are now performing further experiments to improve their process and find more applications for CZTS. Besides solar cells, they've also looked at possibly incorporating the material into biological sensors, hydrogen fuel cells, and electronic circuitry, though it's still too soon to tell when or if any of these ideas will lead to a commercial product.

Sources: University of Utah, IBM Research

About the Author
Jonathan Fincher Jonathan grew up in Norway, China, and Trinidad before graduating film school and becoming an online writer covering green technology, history and design, as well as contributing to video game news sites like Filefront and 1Up. He currently resides in Texas, where his passions include video games, comics, and boring people who don't want to talk about either of those things. All articles by Jonathan Fincher

"as your mother no doubt warned you, putting metal into a microwave can be dangerous."

Will someone please explain to me why putting metal into a microwave is considered dangerous? Metal simply reflects microwaves, just like the walls of the cooking cavity.

Wives tail?

Charles Hart

My understanding is that it could reflect the microwaves back into the magnetron and burn it out. Just ruins your microwave, that's all.

Michael White

@ Charles: Putting metal objects in a microwave can be dangerous because the temperature of the metal can reach dangerously high levels. Very thin metal sheets can usually disperse that heat before becoming dangerously hot. But a chunk of metal are more dangerous because heat at its core cannot quickly dissipate. Below is a link to an article on this topic by MIT Professor Caroline Ross:


All you have to do to melt metal in a microwave safely is encase the microwave with silicon carbide. What happens is the microwave energy gets absorbed into the silicone carbide allowing intense temperatures to melt metal without the metal reflecting and destroying the microwave. :)

Kalab Wood

ok, first what a load of krap, I use my old microwave to melt silver and gold into investments for my jewelry all the time, its a no bubble in your casting and no need to spin hot stuff in a circle or use vacuums to cast stuff with no blown anything just use vent tape to cover vent inside to magnetron to prevent it heating up and bango a nice little blast furnace can be had...the above old wives tale of DANGER DANGER WILL ROBINSON is lame, pay attention and its fine

science ninja

Kalab Hayes Wood FYI all you need is a piece of duct tape over vet hole inside oven and you can melt metals do it daily

science ninja

Do a search on YouTube and you'll find plenty of examples of people melting lead in their microwaves with no apparent side effects and their microwaves are still functional afterwords.


has no one here cooked a pizza in a wave ? the trick is to use foil and cut a hole in the center of the foil to quicken the heating of the center of the pizza, now I personally only have done this about a thousand times or so. I found the trick was to have more food than metal. The important thing to remember is boiling water, it can blow up in your face. OUCH ! not fun, and my mom who knew better did it for the first time a few years ago.

Jay Finke
I sure as heck would not do experiments with metals and then use the oven for food. But as far as things exploding go eggs can be rather nasty, make a mess, and maybe burn you as well if they explode after extraction from the oven. I know how to avoid an egg explosion but have never solved the shards of egg that stick to a ceramic bowl of egg

in a microwave. Trying to scrub that ceramic is not a trivial effort.

Jim Sadler

Use a caustic oven cleaner to clean the ceramic disc.

Just put the disc in a plastic bag, spray with the oven cleaner seal and leave for a while. Anything still stuck can be gone over again.

Nick Hill

Very irresponsible: everyone knows that metal objects will trash a microwave.


The trick with metal is to have no edges or corners. Round objects generally fare well.

Andrew Zuckerman
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