The Engineers who originally
commented on this story said it is a hoax, giving reasons such as the lack of sufficient surface area, and the general non-conductivity of hair. However, in a follow-up interview with the inventor, Milan Karki,
Gizmag answers much of this criticism by getting additional information about the process. See their
report published Oct. 15, 2009.
Here are some excerpts:
A circuit diagram of the Trinity solar cell. (
Source: Gizmag)
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.
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.
Regarding the panels being show powering a light bulb in a fairly dark room, the Gizmag piece points out that the panels powered a battery which then powered the bulb. He also pointed out that the prototype used to produce the claimed 18 Watts was actually 6 x 5 feet, not the 2 x 1.5 feet shown in the photos typically shown.
استفاده از موی انسان به عنوان رسانا در پنل های خورشيدی
آقای ميلان کارکی، مبتکر 18 ساله که ساکن یکی از دهکده های کشور نپال است با همکاری چند تن از همکلاسی های خود، نوعی پنل ذخيره کننده نور خورشید ساخته که در آن به جای استفاده از سيليکون در نقش رسانا از موی انسان استفاده شده است.
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