A portable electronic device includes a battery and an electricity generating device. The electricity generating device includes at least one solar receiving board, at least one controller, a voltage transducer and an accumulator. The solar receiving board is mounted on the outer surface of the portable electronic device to absorb solar energy and convert solar energy into electric energy. The controller is electrically connected with solar receiving board and the voltage transducer to control the electricity generating device. The voltage transducer electrically connected with the controller to transduce the voltage of the generated electricity into a voltage suitable for operating the portable electronic device. The accumulator stores the electric energy and charges the battery when the electrical quantity of the battery becomes low.