Solar panels with cells made with a material called perovskite have been the next big thing for what seems a very long time. How close are we to seeing perovskite modules on residential rooftops?
What Is Perovskite?
Perovskite is a calcium titanium oxide mineral that was discovered in Russia in the 1800’s by German scientist Gustavus Rose, and named after a Russian mineralogist. It’s also found naturally occurring elsewhere – in the USA, Switzerland, and Italy. But other compounds also contain perovskite crystal structure, and such materials can be synthetically manufactured using low-cost fabrication methods.
Perovskite materials have semiconductor attributes, making them a candidate for manufacturing solar panels.
Perovskite Advantages
Tried, tested and trustworthy silicon has been the material of choice for commercially produced solar panels for many years now. But we’re approaching the limits of what can be achieved in terms of conversion efficiency; which is put by some at 31% for a standard cell.
But perovskite cells promise:
- A better sunlight conversion efficiency. They can absorb a broader spectrum of sunlight compared to silicon solar cells, including near-infrared.
- “Tunability”: the ability to capture specific parts of the solar spectrum.
- Manufacturing using various techniques, including inkjet printing.
- Low-cost and scalable production methods.
- Manufacturing with materials that are abundant; although some options are problematic (such as lead).
- Lightweight cells that can incorporate a high degree of flexibility.
- Options for combining with silicon solar cells to create tandem and multi-junction devices.
- Less energy required for production.
Cheaper, versatile and increased efficiency – there’s a lot to like about perovskite. But …
Degradation A Major Challenge
I remember being excited by perovskite’s potential in the early days. But back then and in the years that followed, any research published indicated problems with rapid degradation; something you don’t want in a solar panel that’s going to be sitting on a roof or out in a paddock for decades. The early devices started degrading in just hours or days under certain conditions. They were highly sensitive to moisture, high temperatures, UV light and ion migration.
All of these issues were deal-breakers, but researchers persisted; supported by fistfuls of cash to continue fiddling. Here in Australia, the Australian Renewable Energy Agency (ARENA) has dished out millions of dollars since around 2015 to perovskite projects.
Where Is Research At Now?
Over the last few years, perovskite solar tech developments have accelerated and some big players in the PV industry are now heavily involved.
Effective encapsulation techniques have been developed to protect perovskite solar cells from moisture and oxygen. Thermal stability has been improved, as has the issue of ion migration. Other additives and enhancements have also been developed to address degradation.
Just in the last couple of months there has been a flurry of related news. A very recent example is China’s Longi announcing what it said was a new world record efficiency of 30.1% for a commercial M6 size wafer-level silicon-perovskite tandem solar *cell*. And that may not stand for long as the theoretical efficiency limit of monocrystalline silicon-perovskite tandem solar cells is up to 43%.
Also last month, the UK’s Oxford PV declared it had achieved a world record 26.9% *module* conversion efficiency with a 60-cell residential-size solar panel, again based on silicon-perovskite tandem cells. Just as some sort of comparison, premium silicon-only solar panels have an efficiency around 23%. Even good quality budget panels are achieving around 21% – 22% these days.
When Will Perovskite Solar Panels Be Available?
It’s looking likely the first products to be made commercially available will be solar panels using silicon-perovskite tandem cells. Oxford PV claimed to have the first volume manufacturing line for these cells and plans to scale up to gigawatt volumes within the next few years.
There are several other companies expecting to kick off commercial production this year. But no plan survives contact with the enemy and whether you’ll be able to pick up a panel using perovskite tech in some form in 2024 remains to be seen. We’re halfway through the year and I haven’t spotted any yet.
As for degradation issues, if perovskite solar panels come with what is a standard 25-year performance warranty, manufacturers are going to have to be very certain on degradation allowances to ensure they won’t have a stack of warranty claims down the track.
Perhaps I’ve been turned off a bit by the “soon” hype of the early days, but if/when perovskite solar panels become available for residential installations, I’ll let you go first. You’re welcome.
If you’re interested in gaining a deeper insight into perovskite, here’s a good start. I must admit that when attempting to understand perovskite technobabble, my eyes tend to glaze over and my mind escapes to a fortified compound on a tropical island where Gillian Anderson is feeding me peeled grapes.
Alternatively, to check out conventional silicon modules you can buy right now, compare solar panel specifications and pricing here.
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