Why perovskite is the buzz in the solar tech world

Although you may find it hard to pronounce and spell, ‘perovskite’ is word worth remembering if you're interested in fossil-free, renewable energy. In Japan, scientists and the government hope this material can increase the country’s energy production. British scientists in Oxford are examining the use of minuscule perovskite solar cells in small electrical devices. Different research institutes are reporting over 26 per cent efficiencies for perovskite solar cells.

Professor Feng Gao. Photo: Thor Balkhed, Linköping University.

At Linköping University in Sweden, Professor Feng Gao leads a dynamic research group focused on organic and perovskite semiconductors.
‘Perovskites are a new generation of materials for solar cells. They are low-cost, easy to fabricate, and produce solar cells with high power conversion efficiencies. They can also be made into different colours – which is beneficial for building-integrated photovoltaics for aesthetic reasons. We can also prepare flexible solar panels using perovskites, so they can be easily attached to different surfaces,’ Professor Feng Gao tells THE EDIT.

Why does perovskite matter for the green transition? 

‘Perovskite solar cells have short energy-pack time. It takes only a few months to produce the energy required to produce the perovskite solar cells; this value is more than one year for silicon solar cells. Due to their unique properties (such as light weight, colourful, flexible), perovskite solar cells can be used for applications where it’s difficult to use conventional solar cells. Perovskite solar cells can also be used with other solar cells to form tandem solar cells, which can help achieve even higher power conversion efficiencies.’

When reached by THE EDIT for this interview, Professor Feng Gao reveals that he and his team have breaking news for perovskite as a material for the green transition – with results about to be published in Nature, the world's leading multidisciplinary science journal.

‘Our new results show that we can recycle all the components from degraded perovskite solar cells, using green solvents. New perovskite solar cells made from the recycled ones produce power conversion efficiencies as high as those made from fresh materials. We can even repeat this recycling processes multiple times. These new results will be published in Nature very soon,’ Feng Gao tells THE EDIT.

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Gerrit Boschloo, Professor at the Department of Chemistry at Uppsala University in Sweden, is another scientist interested in the material. His department has been using perovskite in a range of projects since 2012. For Boschloo, perovskite’s greatest potential lies in its uncharted territory. While we know exactly where we stand with regular silicon solar cells, the possibilities with perovskite seem endless.

‘Silicon solar cells work satisfactorily, but we’ve taken them as far as they can go. Perovskite can be even better and more effective. As a scientist, that’s thrilling,’ says Gerrit Boschloo. 

Perovskite facts – pros and cons

Pros:

• Inexpensive and energy-effective to produce: The raw material is easily accessible on a global level and easy to mine.
• Flexibility: Perovskite can be made very thin and semi-transparent, expanding the potential areas of use (e.g. as a thin layer on windows). While silicon solar cells are approximately 200 micrometers thick, perovskite solar cells can be made as thin as 500 nanometers. This difference also significantly reduces the use of raw material.
• Recycling: While perovskite's instability poses challenges in various areas, it also makes it easily recyclable. Through a chemical process, a solar cell can be dissolved and the active substances separated.

Cons:

• Instability: Silicone solar cells are stable and reliably predictable. Perovskite is less stable and may have a shorter life span.
• Lead: Lead is used as an essential part of the material in many of the perovskite solar cells currently being tested, which may lead to health and environmental issues.