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Perovskite crystals are used in solar panels, screens, and camera sensors.
Researchers at Argonne National Laboratory developed a salt trick to address a problem with perovskite crystals.
New volatile low-melting mechanism using salt additives controls perovskite crystal formation at the atomic scale.
In early tests, LEDs made with this technique reached new records for efficiency and lifespan.
Spreading salt on an icy road melts the slick hazard and gives tires traction.
Now, scientists at the U.S. Department of Energy’s Argonne National Laboratory are using that exact same basic principle to fix a problem with perovskite crystals. The lab-grown crystals are used in solar panels, screens, and camera sensors.
In normal settings, as these crystals form, microscopic defects develop that trap electric charges, draining energy and shortening the device’s lifespan.
Now, a new volatile low-melting mechanism using salt additives controls perovskite crystal formation at the atomic scale.
The resulting perovskite crystalline layers feature fewer defects and much more stable performance. This advance powers optoelectronic devices that convert light into electricity.
“Defects have been the bottleneck for perovskites for almost a decade,” said study author Yanqi Luo, a beamline scientist in Argonne’s X‑ray Science division. “If we can remove the major defects, we can finally start building devices that last longer and perform more reliably.”
Perovskites are synthetic crystals built from repeating atomic patterns that absorb light and move electric charges. However, a major structural flaw has blocked the commercial use for nearly a decade. As perovskite films settle onto a surface, tiny atomic defects form like potholes, trapping electric charges, draining energy, and shortening the device’s lifespan.
In this new work, the team described a volatile, low-melting process known as a eutectic method to address the problem. Scientists added two specific salt additives, zinc bromide and methylammonium chloride, to guide the crystal formation.
Just as road salt lowers the freezing temperature of water, these additives lower the melting point of the perovskite ingredients. When heated, the mixture briefly turns into a liquid slush. That brief liquid state buys time.
The atoms get time to settle into a uniform grid rather than rapidly freezing into a scrambled, defect-ridden pattern. As the heat continues, the added salts evaporate entirely, leaving behind a pure, highly stable crystal layer with no structural traps.
At the same time, leftover zinc atoms drift toward remaining fault lines, smoothing out defects before they can ruin performance.
Proving this mechanism required extraordinary tools.
Using high-intensity X-ray probes at Argonne’s Advanced Photon Source (APS) and Center for Nanoscale Materials (CNM), the team mapped composition and optical performance at the exact same time. And watched zinc atoms actively move to repair fault lines in real time.
The study paper noted that the solar cells built with the volatile eutectic method achieved a certified power conversion efficiency of 25.9 percent, while larger perovskite minimodules reached 23.9 percent.
Small-area cells maintained 85.8 percent of their initial efficiency after 1,400 hours of continuous operation at 85°C (185 F). The process also powered light-emitting diodes to an impressive 26.1 percent external quantum efficiency.
This achievement is a step forward for manufacturing, apart from its theoretical success. Manufacturers can now scale up production over large areas without sacrificing quality control, as the salt mechanism enables smooth, consistent crystal growth.
With the Advanced Photon Source recently upgraded to produce X-ray beams up to 500 times brighter, scientists plan to move from snapshot analysis to continuous, movie-like views of crystal growth.
The findings were published in the journal Science.
Mrigakshi is a science journalist who enjoys writing about space exploration, biology, and technological innovations. Her work has been featured in well-known publications including Nature India, Supercluster, The Weather Channel and Astronomy magazine. If you have pitches in mind, please do not hesitate to email her.
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