How Thin Film Works (Frank Jeffrey, Solar Power Entrepreneur)
This entrepreneur is in the thick of "thin film" solar cell manufacturing. Explore more about Jeffrey's take on the future of energy.
Transcript: How Thin Film Works
The easiest way is to start with a description of the device, which is a number of layers, and the way they interact, which does the work of converting the light into electrical power. In our module, we have a bottom electrical contact and a bottom electrical contact to take the power out, but the heart of a solar cell are three layers of semiconductor in between -- a thick layer of non-doped semiconductor and then doped layers on each side. As the light comes through, the top contact is transparent so it lets the light through. It comes into the center layer and is absorbed. When a photon of light is absorbed in the semiconductor, it kicks out positive and negative charge. As it's absorbed, its energy goes into this positive and negative charge. The effect of the two doped layers is to put an electric field inside that middle semiconductor layer -- so that the positive charges are pulled to the top, the negative charges are pushed to the bottom. In the end you have a positive charge available at that top conductive electrode and the negative charge at the bottom. And that's where you make your electrical contacts and bring the current to an external circuit -- from those two electrodes. That's the conversion mechanism. It's an interaction of multiple layers.