LG and Samsung have developed prototype handsets that are recharged by solar panels built into the case.
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 today, 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?
Almost certainly the answer is: not initially. Samsung confirmed that its Blue Earth phone comes with a charger, but added that it's an energy-efficient one drawing just 30 milliwatts in standby mode.
LG says it hopes to commercialise solar-charged phones when it has a model that provides three minutes of talk time after charging for 10 minutes.
In the dark confines of a pocket or bag the phones won't be able to charge, so users will have to ensure they are regularly out in the light. Also as the solar panels occupy the rear of the devices, they'll have to be kept face-down for maximum efficiency - so that might lead to some scratching and scuffing of the display itself.
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Still, these are early days and the development of the handsets goes some way to showing how much companies are thinking about the environment or, at least, thinking about the environmentally conscious consumer and growing market for 'green' products.
Both companies offered no launch timing or pricing for when the prototypes might become commercial models.