Cell phones have been an incredibly important technology – replacing land lines, allowing callers to connect anywhere and anytime, and in some countries eliminating hundreds of thousands of telephone wires. For developing countries, cell phones leap-frogged traditional telephones, minimizing costly infrastructure development. But for all their efficiencies, we still use a lot of energy to charge them. That’s why solar powered cell phones may be the next step towards an efficient technology. Here’s a look at few of the new solar powered cell phones coming on the market. They all debuted at the Mobile World Congress in Barcelona back in February.

First up is the full-touch screen Blue Earth by Samsung. This sleek design is small enough to put in your pocket and still packs enough of a solar cell to completely charge the phone. On top of the energy efficient design, the body of the phone is made from recycled water bottles and contains no brominated flame retardants, beryllium and phthalates, which are super toxic. It has a charger just in case you don’t get enough sun though. Samsung also developed some great applications like a pedometer to tell you how far you’ve walked, a CO2 emissions calculator, and a new user interface that makes activating your phone’s energy savings mode easy to use.  The packaging is minimal and made from recycled materials as well.

LG, also known for great cell phones, debuted their solar powered model in February.  LG’s Solar Powered Cell Phone may not be as sleek looking as the Samsung Blue Earth, but it certainly looks like it’s sturdy and rugged. Leave this phone in the sun for 10 minutes and you’ll get 3 minutes of talk time. And leaving the phone out for longer periods of time will generate even more power. LG has also committed to reducing their impact by packaging their cell phones in more eco-friendly materials. They will use recycled paper packaging without laminate coating and soy inks. Additionally, through their “Life’s Good When It’s Green” initiative, LG will phase out Brominated Flame Retardants (BFR), Chlorinated Flame Retardants (CFR) and Polyvinyl Chloride (PVC) from the manufacturing process by 2010.

The last model to debut is by China-based mobile manufacturer, ZTE, who wants to bring solar powered phones to the masses. Their low-priced model, the Coral-200, is set to cost only $40! The basic, yet slick design is sure to be a pleaser especially at such a low price point. ZTE’s goal with the Coral-200 is to provide a low-cost phone to those that normally don’t have access to the electric grid, but will surely be used by those who do. This phone should get 15 minutes of talk time for every hour set in the sun. ZTE is powering with Digicel to bring this phone to market by June.

With solar phones coming on the market, you can expect all the other manufacturers to debut their version soon as well. It makes sense really – solar cells are becoming more efficient all the time and devices will need to become solar powered to compete in the market. Now leaving your phone out in the sun is a good thing.