New coating covers perovskite solar cells' last Achilles heel

Perovskite is quickly gaining on silicon in the solar cell field, but it has one major drawback – durability. Now, a new treatment has been shown to keep perovskite solar cells working at 99% of their efficiency after 1,000 hours of use.

Silicon solar cells may have had a head start of several decades, but perovskite is rapidly closing the gap after only about 15 years. Not only is its efficiency approaching that of silicon, but it's also cheaper, lighter and more flexible.

But of course, there's a catch – perovskites tend to break down when exposed to the elements, which isn't ideal for devices designed to sit out in the Sun all day, every day, for decades. Scientists have experimented with strengthening them by adding bulky molecules, 2D additives, carbon nanodots made of hair, or quantum dots, among other things.

Now a team has used a new adhesive to protect perovskites. It's called BondLynx, and it was originally produced by Canadian materials company XlynX for other purposes before being tested on solar cells.

The problem with perovskites begins when organic components in the material are activated by heat and light and can escape, weakening the perovskite and damaging other materials in the solar cell. BondLynx is a crosslinker that forms chemical covalent bonds with those organic components, preventing them from wiggling loose and reducing efficiency.

The team treated perovskite solar cells with BondLynx, and then exposed them to long-term heat and light to see how well they fared compared to solar cells that hadn't been treated. The solar cells started with an efficiency of 24%, and retained almost 99% of this after 1,000 hours of continuous exposure to simulated sunlight. By comparison, untreated solar cells lost 35% of their original efficiency under the same conditions over the same time frame.

The solar cells were also exposed to a constant heat of 60 °C (140 °F) for 600 hours. The BondLynx-treated ones managed to hang onto almost 98% of their efficiency over that time, while the control group lost 27% of theirs.

Although the tests were only conducted for a matter of months, the fact that the treated cells barely lost any efficiency at all suggests they should be able to endure for far longer. Along with another recent coating was estimated to give perovskite solar cells a 30-year lifetime, this plucky new contender might have patched up its Achilles heel and soon challenge silicon for solar supremacy.

The research was published in the journal Joule.

Source: XlynX