One of the reasons I think solar photovoltaic power is going to take over the world is that it is scalable in a way no other power source can be. It can be used to build multi-hundred-megawatt power plants, or it can be scaled down. Way down.
How far down? Try less than the width of a human hair.
Solar cells are getting ridonkulously small
South Korean scientists have created solar PV cells that are 1 micrometer thick, hundreds of times thinner than most PV and half again as thin as other kinds of thin-film PV. (The research is in a paper published in Applied Physics Letters last June.)
The cells are made with gallium arsenide as the semiconductor, “cold welded” directly onto a metal substrate, with no adhesive to make them thicker. Remarkably, they produce roughly as much power as thicker PV cells, though in testing, “the cells could wrap around a radius as small as 1.4 millimeters.”
With cells this thin, solar PV can be integrated in all sorts of “wearables” — clothes, glasses, hats, or backpacks with solar cells integrated, continuously feeding power to our portable electronics. More to the point, PV could be integrated into just about anything.