Disclosed is an apparatus for generating electrical energy that includes; a first electrode, and a second electrode spaced apart from the first electrode, and an energy generation layer disposed between the first electrode and the second electrode, wherein the energy generation layer comprises a photoelectric conversion layer and a plurality of piezoelectric nanowires, and wherein when an external force is applied to at least one of the first electrode and the second electrode, the plurality of piezoelectric nanowires are transformed to generate electrical energy.