But stability remains a difficult challenge.
In a recent study, published in Science in April, researchers discovered a new way to build perovskite solar cells with additives that improve efficiency and shelf life. The cells withstood 1,500 hours of high heat and humidity in the laboratory.
The problem is translating these results into the real world. It is difficult for researchers to simulate real-world conditions and silicon has set a high bar, with many manufacturers guaranteeing that their panels will maintain 80% of their performance for 30 or even 40 years.
In recent field trials, researchers found that perovskite-based cells performed better than 90% of their initial levels after a few months. But losing almost 10% of a cell’s performance in that time period will not reduce it.
Another wrinkle is that all these tests have been done using tiny cells. Enlarging perovskites and making larger cells that can be joined into full-size solar panels often lead to setbacks in efficiency and service life.
These challenges make the day when perovskites take over solar markets not as close, or inevitable, as some researchers say it is, Green says.
Adjusting perovskites with methods such as adding stabilizers and materials that protect them from the elements could allow these solar cells to last a couple of decades under normal operating conditions, says Letian Dou, a perovskite researcher at Purdue University. But he predicts it will be a decade or more before perovskites make significant commercial progress.
Despite the challenges, there is a real need for different types of solar cells. That’s especially true now, when demand for solar materials is exploding, says Jenny Chase, head of solar analysis at Bloomberg New Energy Finance.
And perovskites do not necessarily have to compete directly with silicon, because they can be used in tandem cells, where a layer of perovskite is stacked on top of a silicon cell. Because the two materials capture different wavelengths of light, they could complement each other.
None of this is likely to happen unless someone can make much more stable perovskite solar cells. But researchers are certainly not giving up on their promise. As Green puts it, “there’s still a chance someone will actually finish it.”