Alternative or "green" phone chargers are still, at this point, unfortunately more expensive than practical. Fuel cell batteries, for example, offer backpackers a way to keep their phones charged in the wilderness, far away from power outlets. But they're expensive, upwards of $100 for a charger. And fuel cell batteries need their own special rechargers, too. Those cost more money. The great untapped, affordable alternative energy source for charging phones is solar power. A company called SunPartner Technologies wants to apply solar power to to smartphones to provide infinite charging power, and their solution, the Wysips crystal, definitely has potential.
Wysips uses nearly-invisible photovoltaic solar cells to absorb solar energy and convert it into battery power for a smartphone. It comes in the form of a thin layer which is added to the top of a phone's display stack, above the touch layer and LCD components. Now for the drawbacks: the thin crystal layer is currently only about 90% transparent, which means a marginal decrease in display brightness and quality.
"The material, comprised of photovoltaic crystals, is made invisible through a process that bonds the tiny cells with optical micro-lenses," explains Technology Review. "[Wysips sales director Matthieu] De Broca says researchers are continually working to refine the technology, noting that in some cases, it may be possible to reach 92 and even 95 percent transparency (Wysips has reached 90 percent). However, the drawback with improving clarity is that doing so requires decreasing the amount of solar cells used. The challenge then is to find the right balance to ensure that the feature works as a useful addition while also not taking away from the user experience."
Unfortunately, making Wysips more transparent may nullify its practicality. In fact, due to the minimal charge it provides, it may already be impractical. Early impressions of the layer found it visible, though harder to spot dead-on than at an angle. But if a decrease in brightness causes phone owners to crank up their display brightness as a result, Wysips charging capabilities may prove negligible.
For an hour of exposure to sunlight, Wysips should provide about 10 minutes of extra talk time or 20 minutes of music playback. It converts sunlight to energy at approximately 20 percent efficiency. It can also charge off indoor lighting, though at a lower efficiency.
Wysips is certainly efficient enough to facilitate a life-saving phone call to anyone stuck with a dead battery out in the wilderness, but in day-to-day use it's hard to see most people having their phones out enough to build a substantial charge. Still, this is early days for this kind of solar technology. SunPartner Technologies hopes to get Wysips into phones in 2014, and it's only been in development for a couple years. It's a promising start--in another five years, fully transparent solar layers may be keeping all of our smartphones topped off.