Perovskites are one of the most promising new materials for solar cell technology. Now engineers at the University of Rochester have developed a new way to more than triple the material’s efficiency by adding a layer of reflective silver underneath it.
For the better part of a century, silicon has been the go-to material for making solar cells, thanks to its abundance and efficiency in converting light to an electrical current. But in just the last decade, a new contender has rapidly risen through the ranks – perovskite, which is much cheaper and has already caught up to silicon in efficiency.
Now a new study has boosted perovskite’s efficiency by three and a half times, without even tweaking the material itself. Instead, the team found that adding a layer of a different material underneath it changed the interactions of the electrons in the perovskite, reducing an energy-sapping process.
Perovskites and other photovoltaic materials generate electricity by allowing sunlight to excite electrons in the material, causing them to jump out of their atoms, ready to be guided to generate an electrical current. But sometimes, electrons fall back into the “holes” they left behind, reducing the overall current and as such the efficiency of the material. This is what’s known as electron recombination.
The researchers found they were able to drastically reduce electron recombination in perovskite by placing it on a substrate made up of either silver alone, or alternating layers of silver and aluminum oxide. The team says that doing so creates a kind of mirror that produces reversed images of the electron-hole pairs, which lessens the likelihood of electrons recombining with the holes. In tests, the engineers showed that adding these layers boosted the efficiency of light conversion by 3.5 times.
“A piece of metal can do just as much work as complex chemical engineering in a wet lab,” said Chunlei Guo, lead author of the study. “As new perovskites emerge, we can then use our physics-based method to further enhance their performance.”
The research was published in the journal Nature Photonics.
Source: University of Rochester
What does that men in practical terms? That we could have PV modules that have 60%+ efficiency? I thought that was theoretically impossible...
While the summary is extremely....light... on details, the concept seems pretty basic (and sound). I am floored no one has previously thought to try this.
If this ~2x holds up, it will go a looooong way to enabling mass production of perovskite base panels simply because current SOTA (State of the Art) formulations could remaining at or above acceptable performance levels for longer periods.. if a perovskite based panel lasts as long as a normal silicon based panel.. and provides comparable output over that period.. then it's lower overall cost and more strategically (geographically/nationally) producibility become compelling.
"boosted the efficiency of light conversion by 3.5 times": ???
These assertions must be explained, or the article is not ready to be published.