And Spaghetti grows on trees.
Commercial bog standard PV cells already have efficiencies in the 12-18%. The record is currently around a phenomenal 40%, which is even better than photosynthesis. 500 times a standard 10% efficiency gives 50 times more electrical energy generated compared to the radiation energy in the sunlight to begin with. What this kid should then do is then produce some light using the latest LEDs powered from his 3D solar cell and then shine the light produced on to another of these 3-D solar cells and do this again and again until he can power a small city with the light from the light produced by the maglite solitaire at the beginning of the cascade!!