Samsung's phone is called Blue Earth and is a touchscreen model with rounded corners designed to look, said Samsung, like a "well-rounded pebble." Continuing the environmental theme, the phone is made from recycled plastic and doesn't include harmful substances like brominated flame retardants (BFRs), Beryllium and phthalates.

The solar cells on the phone occupy most of the rear of the phone's case.

LG didn't release much information about its prototype phone, but images from the company show what appears to be a version of its KF750 Secret handset with -- like the Samsung phone -- solar cells covering the rear of the phone's case.

In both phones, which were almost simultaneously announced by the companies in South Korea on Friday, the solar panel doesn't provide enough power to run the phone directly and is used to recharge a conventional battery inside the device.

So will the new phones mean an end to chargers?