Could Perovskites Provide Cheap, Long-Term Solar Power?



In my ViewPoint column this month, I wrote a little about how governments are putting vehicle manufacturers under pressure to become more efficient and sustainable. This is not just a problem for the automotive industry. Governments themselves are trying to meet targets that they have either set for themselves or signed up to through international agreements. One aspect of that is renewable energy. Boris Johnson, the UK’s prime minister, set out a commitment in October this year to build the country back greener after the coronavirus pandemic and reduce net emissions to zero by 2050.

During the launch, he also committed the UK to generating up to 1GW of energy by renewable techniques by 2030. This figure is 15 times the energy that the UK currently generates from renewable sources. Other countries have similar commitments, Germany plans to transform its electricity supply system to a wholly renewable-based electricity by 2050.

Clean energy comes in many different forms - solar, geothermal, wind, hydroelectric, tidal etc. Each country runs a mix of these as its geography and climate allows. The problem for them is much the same as automotive manufacturers, and that is how to make the generation of energy more efficient. Renewable energy can often take up large physical areas as large wind farms or solar farms are required to generate enough power to do anything useful. Some countries just don’t have the land to spare.

The key to solving this problem could be new materials or techniques that would allow more generation to take place in smaller areas or, in some cases, get rid of the need for areas devoted solely to power generation. For example, solar panels, as they are currently manufactured, have a maximum efficiency that we are getting pretty close to at present. Other ways of generating solar energy have been developed, but are not viable at a large enough scale to be useful at present.

One of those new materials is metal halide perovskites. Perovskite solar cells are thin films of synthetic crystalline made from cheap, widely available chemicals like iodine, carbon and lead. They can be fabricated by printing, making them much more cost effective and sustainable than traditional materials. A high absorption coefficient allows films of around 500 nm to absorb the complete visible solar spectrum. The combination of those features means that perovskites could potentially be used to create cheap, highly efficient, thin, light and flexible solar cells.

The problem at the moment is that the material is unstable and difficult to make. Now, a team of researchers at Stanford has made a breakthrough and developed a quick way to produce stable perovskite cells and assemble them into solar modules. This breakthrough could be a game changer for the solar industry if it pays off. If the cells prove reliable enough to last for 30 years, the cost of solar energy could be more than halved. For more information on perovskites -