But stability remains a tough challenge.
In one recent study, published in Science in April, researchers discovered a new way to build perovskite solar cells with additives that improved efficiency and lifetime. The cells withstood 1,500 hours of high heat and humidity in the lab.
The problem is translating these results into the real world. It’s hard 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 testing, researchers found that perovskite-based cells performed at over 90% of their initial levels after a few months. But losing nearly 10% of a cell’s performance in that time span isn’t going to cut it.
Another wrinkle is that these tests have all been done using tiny cells. Scaling up perovskites and making the larger cells that can be strung together into full-size solar panels often leads to setbacks in efficiency and lifetime.
These challenges mean the day when perovskites take over solar markets is not as close at hand, or inevitable, as some researchers make it out to be, Green says.
Fine-tuning perovskites with methods like adding stabilizers and materials that protect them from the elements could eventually enable these solar cells to last a couple of decades in 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 meaningful 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 would not necessarily have to compete directly with silicon, because they can be used in tandem cells, where a perovskite layer is stacked on top of a silicon cell. Because the two materials capture different wavelengths of light, they could complement each other.
None of that is likely to happen unless someone can make perovskite solar cells that are far more stable. But certainly, researchers are not giving up on the promise. As Green puts it, “There’s still a chance that someone will really nail it.”