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Is there something in the hair? The tale of a solar cell made with human hair


October 15, 2009

Debate is good. Debate is healthy. Debate is currently raging after an article recently appeared on the UK's Daily Mail website announcing a revolutionary solar cell that's made using human hair. A group of teenage students from Nepal claim to have replaced expensive doped silicon used in conventional solar panels with cheap and readily available human hair to produce a cell capable of generating 9V (18W) of electricity. Curiosity got the better of Gizmag's Paul Ridden, who contacted one of the team to find out more.

Although the Daily Mail article has been used as a primary source reference for many of the subsequent articles that have appeared, it lacked any great detail on how the cell was made and how it was claimed to work. This in turn has led to a great deal of debate on whether such a cell could actually work as claimed, or rather, as reported. Gizmag managed to track down team member and inventor of the cell, 18 year-old Milan Karki and asked about the project.

An overview

Working with fellow students from the Science and Technology Guild at the Trinity International College in Kathmandu, Karki appears to have based his innovation on a dye-sensitized solar cell rather than the more familiar layered silicon design. Karki was happy to share some details about his invention with Gizmag but was (naturally) somewhat guarded about full disclosure pending a patent application.

To create his cell he took a piece of glass, stained one end with some silicon dioxide to act as a cathode and fixed oxidized copper to the other (the anode). Human hair was soaked in organic salts and then stretched between the two connections and held in place. A thin layer of graphite covered the silicon end and the copper end left exposed to light (sunlight/UV). A few drops of iodine on the hair act as an electrolyte.

It's said to create electric current when light hits the oxidized copper end and knocks out some electrons which then travel down the salt-soaked hair to the silicon end. The function of the hair is not to soak up sunlight but to act as a bridge in the circuit to help electrical current flow, in other words as a conductor or semi-conductor.

Several of these cells are placed together in series and the power produced when exposed to sunlight is then used to charge a 12-pack of AA rechargeable batteries.

The public speaks

Underneath the Daily Mail article (in common with other sites which have used the article as source for their own stories) you'll find comments from both well-wishers and those who question the validity of the solar cell. The latter having various issues with the science behind the discovery. One commenter, experienced engineer Craig Hyatt, went so far as to create a debunking website where he tackles many of these problems head-on.

Of all the issues, probably the main one is that human hair does not conduct electricity. That hair can and does produce a static charge there is no doubt but as to whether it can conduct an electric current, all the evidence prior to this announcement clearly points to hair being an insulator rather than a conductor, such as the controlled experiments conducted by R A Fischer & Co in 1998.

Karki points to the porous quality of the cortex of human hair and told Gizmag that when pre-soaked in organic salts, the electrons flow through the hair assisted by the conductivity of the salts. He confirmed that while other porous materials had been not been investigated to see if there was a better and cheaper material available, numerous tests with varying colors of hair showed black hair to be the best promoter for those electrons. He attributes this to the higher levels of pigment found in dark hair.

And that leads to another point of contention. Melanin does indeed have electrical properties but as Hyatt points out: "as long as it's bound to the keratin in hair, it is insulated and doesn't come in contact with any electric charge. If there are any active melanin molecules present, they only act as a pigment or convert UV into heat which is how they protect your body from solar radiation." In order to conduct electricity the melanin would need to be "isolated from keratin and concentrated."

Karki says that the melanin merely acts to enhance the flow of electricity and it's the organic salts which actually do most of the work. In fact, he admits that once the hair dries out, the cell stops working but says that getting the cell operational again is a relatively simple matter.

The dark room

Most of the press photographs show the student team holding up the solar panel and powering a light bulb in what appears to be a very dark room. Even the most efficient solar cells currently available need direct sunlight to operate. Olivia Lang, the journalist who originally broke the story, was "out of the office" at the time of writing but Gizmag managed to contact the photographer, Tom Van Cakenbergh. He told us that: "the philosophy of the panel is that it charges a battery first. Indeed I saw it cannot provide enough power for a light directly. The images are shot with the whole set up: panel, battery and bulb."

Experienced teacher of electronics Tony Kuphaldt told Gizmag that this amounted to: "claiming I've made a fantastic new water pump out of human hair, then on the day reporters show up with cameras I demonstrate how a tank full of water - filled the night before with my amazing new pump - is actually full of water today." Kuphaldt also pointed out that silicon dioxide is an insulator too and is "widely used as a nonconducting substrate material in the semiconductor industry for precisely this reason."

However, Van Cakenbergh says that he was also present at a small demonstration where: "the solar panel was connected to a meter (no batteries or whatever) and then we moved it from shadow to sunlight. The numbers on the meter went up a lot." Although, by his own admission no expert in solar energy, he says that on checking the panel over he saw only "the hair, the metal buds, dark paper, electrical wires all attached to a wooden board."

Given that the sacrifice of electrons in a silicon-based cell is not overwhelmingly efficient at converting the sun's energy into electricity and that dye-sensitized cells are even less so, the 2ft by 1.5ft panel featured in the press shots appears to be a bit on the small side to produce the reported output. Karki confirmed to Gizmag that the prototype used to produce the claimed 9V (18W) reading was in fact 6ft by 5ft.

What do you think?

In the absence of any professional technical expertise at the reported demonstration, eye witness reports and the claims of the inventor would lend themselves to the conclusion that the panel doesn't produce enough electricity to power a light bulb but enough to trickle-charge a set of batteries. Exactly how that happens has been and continues to be the subject of much debate and whether the system proves efficient enough and robust enough to have commercial applications remains to be seen.

Karki says that a couple of panels have been sent out to districts in Nepal for feasibility testing. When the patent process is finished with, the Trinity team will be looking to market the invention. More important for some perhaps, at the same time Karki says he will be proving their detractors wrong by disclosing the full details of the solar cell. Something that will no doubt add even more fuel to the debate.

By now you're probably drawing your own conclusions and we'd like to hear them via the comments below.

(All images supplied by Milan Karki)

About the Author
Paul Ridden While Paul is loath to reveal his age, he will admit to cutting his IT teeth on a TRS-80 (although he won't say which version). An obsessive fascination with computer technology blossomed from hobby into career before the desire for sunnier climes saw him wave a fond farewell to his native Blighty in favor of Bordeaux, France. He's now a dedicated newshound pursuing the latest bleeding edge tech for Gizmag. All articles by Paul Ridden

I think this should be a regular part of GIZMAG.

Looking at "inventions" that seem too good to be true. Actually requesting tests and even testing the products or "inventions" themselves!!!

What about all those perpetual motion machines??

Water for gas??

This could be an unending source of very valuable articles.

It could also be YOUTUBE fodder.

2nd May, 2015 @ 5:23 a.m. (California Time)

Thanks for this follow-up coverage. It would appear that you've addressed the most serious qualms about the claims made by the Nepalese students. While not all questions are addressed, as least you have put this back into the realm of "wait and see" rather than "hogwash, ignore."

I've added reference to your article and points in our feature page on "Human Hair Solar Panel by Milan Karki" at PESWiki.com.

Nice work.

Sterling Allan
2nd May, 2015 @ 5:23 a.m. (California Time)

Reply to Sterling Allan: Aw c'mon! The article doesn't address any concern about this so called "invention" but rather shows even more conclusively that it makes absolutely no sense. Take a look at the schematic. The diode is backwards and the way all the components are arranged is crazy. It basically turns out that he's using a bunch of chemicals and the hair isn't doing much of anything! He admits he didn't do a controlled experiment that involved trying some other fiber. And now he claims that he needs a 5x6 sheet of glass to build it? Do you have any idea how much glass costs? Just the glass alone (not to mention all the chemicals) makes the cost astronomical. Also, given that the drawing and explanation make no sense and can't possibly work, I am sure that the photographer got pwnd. You notice the photographer said the "numbers went up" not that he saw how much voltage and current this solar panel was generating. It could have been a cuprous oxide cell generating 9V at 10 microamps for all he knew. Anybody with the slightest bit of understanding and plain old common sense can immediately spot this for a hoax, and now that I've learned more details, I can't see how it can be anything but a deliberate hoax. Leave it in the "hogwash,ignore" column where it belongs!

2nd May, 2015 @ 5:23 a.m. (California Time)

Reply to froginapot regarding "What about all those perpetual motion machines??" Speak of the devil. When I saw the the Sterling Allan comment about peswiki, I was curious and Googled him. Here\'s one of the top links I found: http://www.99polls.com/poll_66574 It turns out he actually does think so-called magnet motors and other "free energy" schemes work... which probably explains why he also believes hair can replace silicon in solar cells. There's a solar sucker born every minute.

On a serious note, I think it might be a good idea to do an in-depth examination of some of these wacky schemes... similar to this article. The first one I'd like to see is one about how cuprous oxide cells do not scale up and you can't power your house with them. So don't spend $29.95 on the instructions, OK? :)

2nd May, 2015 @ 5:23 a.m. (California Time)

very interesting.on another note .when i first saw the "neal tank"i was very excited and since then i have built a few machines to find out if bob neals claims are true.i xperimented with nozzles and venturi injectors but got no decent results.however my engineering expertise may be at fault. my grasp of the second law of thermodynamics is getting better,but i'm stil not sure.is the "neal tank" a fake?help please. ps.i understand the stirling engine fairly well,so i dont think i'm an idiot. jochen from cape town.faneng@telkomsa.net

Jochen Demnitz
2nd May, 2015 @ 5:23 a.m. (California Time)

@Jochen Demnitz: I looked this "neal tank" up on Google and found a reference to patent 2,030,759. I searched this patent on www.uspto.gov and read it. It looks like rubbish to me. You should know that the existence of a patent isn't a guarantee that an idea will work in practice. I read an anecdote claiming the inventor demonstrated this invention, but you should know that patent engineers can be fooled just like anybody else. Ideas like this float around the internet and are mainly supported by websites promising to reveal the mysterious "secret" ... as long as you are willing to pay for it. Trust me. There isn't any "secret", there aren't any "men in black", there's no "big oil conspiracy", there's no "free energy", and most of all there's no such thing as a free lunch. If you really want to contribute, then take all the effort spent on chasing impossible dreams and get rich quick schemes and channel it into getting a good science education. Then take that education and do some research on something practical. That's not to discount tinkering, which is a lot of fun and can produce useful results. I do a lot of tinkering in my own garage, but I try to do it in a systematic way and I don't waste my time on stuff that violates the laws of physics.

Facebook User
2nd May, 2015 @ 5:23 a.m. (California Time)

What sort of unit is 9V (18W)??????????

2nd May, 2015 @ 5:23 a.m. (California Time)

I'm a firm believer in progress - with history showing us over and over again that progress comes from the most unexpected quarters - so, rather than spend anytime disproving it, provide them with the encouragement to prove it - and if they fail, give them the kudos for trying. And for them naysayers - if you can't lead, get out of the way!

2nd May, 2015 @ 5:23 a.m. (California Time)

@WMA "...give them the kudos for trying. And for them naysayers "if you can't lead, get out of the way!"

I got news for you. The whole scientific process is based on "naysayers": the first being experimental controls and using critical thinking, then the investigator's teachers and colleagues, and finally journal paper reviewers. A kid ought to get "kudos for trying" for working hard, being methodical, doing good research, and producing a meaningfuly result... not slapping together a bunch of embarrassing nonsense and unleashing it on the public. Karki is old enough to know better, and he deserves every bit of the smackdown he's getting.

2nd May, 2015 @ 5:23 a.m. (California Time)
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