A NEW solar cell thatimitates Mother Nature’s way of converting sunlight to energy is making itsdebut in a variety of consumer products.
The technology uses a photosensitive dye to start its energy production, much the way leaves usechlorophyll to begin photosynthesis.
The dye-sensitized cellswill be used to provide power for devices ranging from e-book readers tocellphones — and will take some interesting forms. For e-book readers, forexample, the cells may be found in thin, flexible panels stitched into thereader’s cover. But such panels will also be housed in new lines of backpacksand sports bags, where they can recharge devices like cellphones and musicplayers.
The technology, long indevelopment, will work best in full, direct sunshine, said Dr. Michael Grätzel,a chemist and professor at the École Polytechnique Fédérale de Lausanne inSwitzerland. But the cells will also make good use of dappled and ambientlight, including the indoor light of fluorescent bulbs, he said.
Most photovoltaic cellsare based on silicon or related inorganic materials, not dyes. Dr. Grätzel andan American colleague, Brian O’Regan, first reported on the new type of cell inthe journal Nature in 1991, and Dr. Grätzel said that he and other colleagueshad been working since then to refine the technology. Now G24 Innovations,a company in Campbell, Calif., that has licensed the technology, is using it tomake solar panels at its plant in Cardiff, Wales, said John Hartnett, G24’schief executive.
Some of the panels willbe placed on covers designed as an accessory for Sony e-book readers, said Tobi Doeringer, thedirector of global sales at Mascotte Industrial Associates, a Hong Kongcompany that makes bags to carry cameras, phones, sports equipment, electronicgames and other products.
Mr. Doeringer said thecovers, costing about $99, would be available by March. The cover supplies thepower via a plug in a cradle along its spine.
The panels will also beinstalled on tennis bags, backpacks and messenger bags that have batterychargers within, as well as on bicycle, golf, shopping and beach bags. Pricesof the bags will typically range from $149 to $249, he said, depending on thematerials and size of the bag. Owners can plug their phones and music playersinto the bag for recharging, using a USB cord.
Some bags are alreadyavailable, including messenger bags from Tonino Lamborghini, a brand licensed anddistributed by Mascotte. Others will be on the market by the end of the firstquarter, he said.
The solar panels have 11cells each, said Kevin Tabor, director of science and research at G24. Wiringgoes from the panel to a battery pack in the bag, he said. It takes about sixto eight sunny hours outside for the panel to fuel the recharger, he said, butlonger indoors.
The performance of thedye-sensitized cells has improved steadily in the laboratory, Dr. Grätzel said.“Our dyes and electrolytes have changed,” he said, and the cells have becomemore efficient at converting sunlight to electricity.
Within the solar cell,the dye is painted in a thin layer on a porous titanium dioxide scaffold tocollect light and, in a series of steps, create power.
AN Australian company, Dyesol,supplies materials to G24 Innovations and other companies developing dye solarcell technology, said Marc Thomas, the chief executive of Dyesol’s NorthAmerican operations in Sacramento. Dyesol provides the dye, titanium pastes andthe electrolytes for the thin-film technology, he said. Titanium dioxide is acommon, inexpensive ingredient that is used, for example, to whiten toothpaste.
Mr. Thomas noted thatDyesol customers were planning to use the technology to prolong battery life indevices like wireless sensors and keyboards.
Thecells draw on many surprising sources of light, he said, including some thatoffer the barest trickle. “We’ve even had a case where we have
generatedvoltage from moonlight,” he said.