Simply put, the photovoltaic effect occurs when a photon strikes an electron, and knocks it out of orbit. The free electron leaves behind a positively charged "hole," thus producing a flow of current. The amount of sunlight that a given substance can convert into electricity is called its conversion efficiency. Many factors affect this efficiency rating. They include the amount of energy required to knock an electron from orbit, which is called the band gap; the atomic structure of the material, which can inhibit or aid the flow of electrons and holes once the photovoltaic process begins; the thickness of the material needed to absorb sunlight; the cost of making the material; and its ability to withstand wear and tear.
Photovoltaic researchers have spent the past decade refining the basic solar cell made of crystalline silicon, a substance that is conducive to the photovoltaic process because of its perfect atomic ...
