Perovskite Degradation – Major Breakthrough

Scientists the world over have been trying to create inexpensive, highly efficient solar cells out of perovskite, and this week some new research has come out which moves us another step in that direction. Perovskite degradation occurs rapidly when the naturally occurring mineral exposed to ambient air, which is quite the issue for a solar cell. According to the NREL team,Researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) have manufactured an environmentally stable, high-efficiency perovskite solar cell. Another step closer to commercial sale of perovskite solar cells!

Perovskite Degradation and the NREL Research

Perovskite Degradation
Perovskite Degradation (source: wikipedia.org)

CleanTechnica have written an article about the NREL Research on perovskite deterioration in ambient air and are reporting that the research team have successfully tested a perovskite solar cell in ambient conditions with no protection for 1,000 hours – with a fantastic result that 94% of conversion efficiency was retained.

The scope of the research is a little over our head, but if you’re interested in learning more about the study “Tailored Interfaces of Unencapsulated Perovskite Solar Cells for >1000 Hours of Ambient Operational Stability you can click the link to read about it via Nature magazine. 

In simplest form, previous methods of protecting the perovskite have focused on creating a protective enclosure around the solar cell. Instead of that, they focused on the ‘weakest link’ in a perovskite solar cell and replaced it with a different molecule.

“Each interface and contact layer throughout the device stack plays an important role in the overall stability which, when appropriately modified, yields devices in which both the initial rapid decay (often termed burn-in) and the gradual slower decay are suppressed.”

Perovskite research is moving along at a fantastic clip. Here are some other updates on this technology we’re really excited about:

 

 

 

Silicon Alternative for Solar Cells

Researchers from the University of Cambridge in the United Kingdom and MIT, the National Renewable Energy Laboratory and Colorado School of Mines in the USA have been hard at work coming up with a silicon alternative for solar cells – given that silicon needs to have extremely high levels of purity and as such is very energy intensive to produce. After looking at options such as perovskite solar cells, the team have been using the “green element”, bismuth, in tests to create a low-cost solar cell.

Silicon Alternative for Solar Cells  – Research

The vast majority of solar cells we see on rooftops or as part of solar farms are created from silicon – a very efficient element in terms of its ability to convert light into energy, but also, as mentioned, expensive (and energy intensive) to produce.

There has been a lot of research on perovskite solar cells as a possible alternative, which we have reported on previously. Since lead is an integral part of the perovskite cell’s chemical structure, there’s still a search for a cheap, non-toxic material to create these cells – enter Bismuth.

Bismuth - A Silicon Alternative for Solar Cells
Bismuth – A Silicon Alternative for Solar Cells (source: Steve Penny, University of Cambridge via ScienceDaily.com)

According to ScienceDaily, Bismuth is a heavy metal like lead, but it is non toxic. Previous tests of Bismuth oxyiodide indicated that its efficiency may be too low for solar and it was also easily degraded in liquid electrolytes. However, further research has shown it may in fact be a suitable replacement for silicon in that it’s inexpensive to produce, can be very efficient in converting light into energy, and is eco-friendly.

“Bismuth oxyiodide has all the right physical property attributes for new, highly efficient light absorbers,” said co-author Professor Judith Driscoll, of the Department of Materials Science and Metallurgy. “I first thought of this compound around five years ago, but it took the highly specialised experimental and theoretical skills of a large team for us to prove that this material has real practical potential.”

We’ll see how this exciting research progresses – but in the meantime if you want to read about the study in detail you can find this journal: Strongly Enhanced Photovoltaic Performance and Defect Physics of Air-Stable Bismuth Oxyiodide (BiOI)Advanced Materials, 2017; 1702176 DOI