Built-in solar cells for Smartphone is very power saving concept. With this technology even laptops, phones can be used with out charging – energy saving.
An ingenious researcher at the London Centre for Nanotechnology has managed to squeeze a bunch of photovoltaic (solar power) cells into a very interesting location: Behind your smartphone’s display.
According to Arman Ahnood, who unveiled his findings at the Materials Research Society late last year, only 36% of the light produced by an OLED display is projected straight out; the rest is wasted, either as scattered light or bleeding from the edge of the display. In a fairly basic leap of logic, Ahnood created photovoltaic cells that line the back and sides of OLED screens to capture this wasted light: Voila, free, harvested energy that can then be used to power the phone or charge the battery.
The best bit, though, is that Ahnood’s cells take the form of a thin film, much like OLED and LCD displays themselves. The idea is to bond this photovoltaic layer to the stack of films that make up an OLED display (pictured below), ultimately producing OLED screens that automatically harvest wasted light. Furthermore, because OLED and LCDs are not completely opaque, these thin-film photovoltaics also gather ambient light, be it from overhead lights or the sun.
Ahnood’s system — which includes a supercapacitor and some circuitry — has an average efficiency of 11%; significantly lower than commercial photovoltaics that are reaching 30%, but remember that’s free energy. For a typical 3.7-inch smartphone screen, the system can currently output a total of five milliwatts; again, not a lot (maybe a hundredth of what a modern smartphone uses), but better than nothing.