Researchers at Stanford University developed a solar-powered generator made of purely carbon. This is also known as a photovoltaic cell, which is the most common type of solar-powered generator.
Photovoltaic cells are the electricity-generating parts of a solar panel. Solar panels are just a protective housing for solar cells, which are fragile semiconductor devices.
The significance of this invention is due to the abundance and low cost of carbon. Unlike typical silicon wafer solar cells which are often rigid, it is deposited onto a substrate (surface) from a liquid solution.
Thin film solar cells were invented long ago, but, this is just a perk which makes it easy to manufacture solar cells using small amounts of the semiconductor material required, and it facilitates the manufacture of flexible and non-flat solar panels in general.
Source: Stanford Website