I have heard that most solar panels use polycrystalline silicon. It seems like a very expensive material. Are there any other materials we can potentially use to capture photons in solar panels?
The operation of a photovoltaic (PV) cell requires three basic attributes:
The absorption of light, generating either electron-hole pairs or excitons. The separation of charge carriers of opposite types. The separate extraction of those carriers to an external circuit.
The problem is finding a material that is cheap, manufacturerable, holds up over time and is efficent.
Other solar cell technologies such as perovkites could potentially be manufactured very cheaply and are competitive with silicon in efficiency. They are relatively new, and will require more research and commercial development before coming to market. We have decades of experience with silicon, and entire supply chains to support the manufacturing of silicon solar cells.
Yes, there's loads of options.
Copper indium gallium selenide. Can be on flexible substrate.
Cadmium telluride. Two unpleasantly toxic metals. The other thin film technology.
Perovskite. Not yet commercialised.
However, conventional silicon technology has achieved huge cost reductions through economy of scale, which makes it hard to catch up to. Even for the expensive monocrystalline stuff made by slicing crystals into thin layers with diamond wire saws.