Question: How could you make solar cells cheaper to produce?

Paul Coxon answered on 10 Mar 2014:

Generally, there are two main ways towards cheaper solar power:

1. Use materials in cells that can be made very cheaply, but these have the downside of being relatively inefficient at converting light to electricity, and will need to be replaced after a few short years.

2. Develop highly efficient cells, but these can be expensive to produce owing to the costs associated in producing them.

Recently new materials called perovskites have been investigated which can allow us to get the best of both worlds – highly efficient solar cells but also cheap to make. Perovskite solar cells are made by spreading the material on a sheet of glass or metal foil, almost like a paint which makes them very cheap to produce. Since 2012 the efficiency of perovskite solar cells has reached impressive levels, just a few percent less than the best silicon solar materials today.

My own research focuses on making cheaper and more efficient solar antireflection coatings. These help as much light as possible be trapped within the solar material instead of being reflected back and wasted. The process I use involves immersing silicon wafers into molten calcium or lithium salts and electrochemically extracting the oxygen layer which sits on the top surface. The surface is made up of tiny columns of silicon (sometimes called penguin silicon, because it looks like a colony of penguins) which look extremely black.