Published on May 2nd, 2014 | by Guest Contributor2
60 Years of Solar Cells!
May 2nd, 2014 by Guest Contributor
Originally published on Suniblog.
By David Baldwin
The newsreel is just 90 seconds long. It is incredibly — and, to me, endearingly — crude, ragged, and inept. Against a background of loud, out-of-tune orchestral music, a narrator speaks of harnessing the power of the sun, as the camera shows us (a-ha!) the setting sun, a shot lasting a full thirty seconds. This leads to a shot of “The Bell Solar Battery,” which less resembles the eighth wonder of the world than a wall socket that escaped. We then see a couple of nerdy scientist-types standing outdoors. One of them talks into a microphone: “Do you hear me? Do you hear me?” A third scientist, who does hear the first one on his radio receiver, solemnly waves. Then we’re back to the sun again, as the narrator floridly concludes: “Indeed, Man has at last dipped his hand into the sun and drawn down a spark to warm the hearts of men!”
The film may seem like a very clever parody of the kind of lovably stodgy newsreel shorts that older generations grew up on, but it isn’t. In fact, it records a major scientific breakthrough: exactly 60 years ago, on April 25, 1954, the first practical solar cell was publicly demonstrated. The scientists responsible — Daryl Chapin, Gerald Pearson, and Calvin Fuller — were not flamboyant inventors like Thomas Edison. They were exactly as the movie depicts them: unassuming, corporate scientist-technicians. Yet they helped launch a billion-dollar industry, one that may help lead us all out of fossil-fuel dependence and the resulting climate change.
Of course, the three men didn’t “invent” solar power. Photovoltaic phenomena were first recorded in 1839 by Edmond Becquerel. Albert Einstein won the Nobel Prize in 1921 for his explanation of the photoelectric effect. By 1954, people had been producing electricity from the sun for a long time. The problem was not making it possible but making it practical: existing selenium cells generated electricity equal to less than half of 1% of available solar energy.
Ironically, according to an article by John Perlin, the trio of scientists, like Columbus, stumbled upon their discovery while looking for something else. Bell Telephone had long noted that dry cell batteries didn’t work for long periods in tropical climates. Chapin, who worked at Bell Labs, suggested solar as an alternative source of battery power, and he started research in early 1952. But he got nowhere with selenium. Chapin brought in his friend Pearson, who brought in Fuller, and the two suggested substituting silicon, which worked much better.
The biggest remaining problem was accessing the electricity produced. The issue was the location of the positive-negative junction over which the current flowed, and their challenge was to make this junction as close as possible to the cell’s surface, so leads could be attached to it. Fuller found the solution by treating silicon strips with arsenic and placing them in a furnace to coat them with an ultra-thin layer of boron. Because the p-n junction was now so close to the surface, the electricity generated by the sun — 6% of the available solar energy — could be easily tapped into a usable current.
It was this device that the three men demonstrated in Murray Hill, New Jersey, in April 1954. The press at the time was more impressed than a modern viewer of the newsreel is likely to be. The New York Times, for example, posted the event as a page one story the following day. The experiment, wrote the Times article’s (uncredited) author, marked “the beginning of a new era, leading eventually to the realization of one of mankind’s most cherished dreams – the harnessing of the almost limitless energy of the sun for the uses of civilization.”
Today, “civilization” is embracing the solar cell as never before. The key to solar’s growth in recent years has been a series of breakthroughs — including new financing options — that have made converting to solar much cheaper than it ever was. The common myth that solar is impractical or unaffordable is now just that — a myth — and you can adapt solar power to your family’s particular logistical and economic circumstances. When you choose solar, you’ll not only save money, help to make America energy independent, and behave responsibly toward the environment. You’ll be standing on the shoulders of (humble) giants.