Researcher packs solar cells behind smartphone display, harvests wasted light

This one’s sheer brilliance, anyway you look at it. Arman Ahnood, a London-based researcher working at London Centre for Nanotechnology, through a series of findings concluded that on any given OLED smartphone display, of the total light emitted by the screen only 36 percent is projected straight out, the rest gets wasted in indefinite ways - scattered light or bleeding from the edge of the display. What was only logical then, Ahnood packed in photovoltaic, or solar cells lining the edge and at the back of the screen to capture in the wasted light. With this expertise, Ahnood has an ingenious method at hand to not only power the smartphone, but also charge the battery. A report in IEEE Spectrum states that at the Materials Research Society’s fall meeting in Boston, Arman Ahnood told his fellow researchers that mankind was fast progressing towards the day when phones would “never have to be plugged-in”, which even in conception is brilliant.

Is this the future? (Image credit: Extremetech)

Explaining the system better, the report states, “…instead of charging the battery directly, which would have involved adding complex circuitry, they worked with the energy group at Cambridge’s Centre for Advanced Photonics and Electronics to integrate a thin-film supercapacitor for intermediate energy storage. This combination of photovoltaics, transistors, and supercapacitor yielded a system with an average efficiency of 11 percent and peak efficiency of 18 percent. If the PV array converts 5 percent of ambient light to electricity, the energy-harvesting system can generate as much as 165 microwatts per square centimeter under the right lighting conditions. For a typical 3.7-inch smartphone screen, that equates to a maximum power output of 5 milliwatts, “which is quite useful power,” says Ahnood, though that’s only a fraction of a smartphone’s power needs.”

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For those wondering how a stack of solar cells packed behind one’s smartphone screen would look like, Ahnood’s technology are in the form of a thin film, almost similar in appearance to the displays, themselves. Interestingly, the researcher aims to pack the solar cells behind the thin film of the OLED display and in this way the wasted light will be automatically harvested off the screen, itself. The report also reveals that considering that the OLED, LCD displays are not opaque, the photovoltaic cells will be able to gather light better.