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Briefly liquid grain boundaries lift UC San Diego-led perovskite devices to 24% to 26% efficiency
UC San Diego-led researchers report perovskite solar cells and LEDs at around 24% to 26% efficiency, grown with a temporary liquid phase. In the one durability result the report describes, the solar cells kept most of their efficiency through eight weeks of simulated sunlight.
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What happened
- David Fenning, a UC San Diego professor of chemical and nano engineering, led the work; researchers at Princeton University and South Korea's Sungkyunkwan University also took part.
- Zinc bromide and methylammonium chloride went into the perovskite solution as additives; when heated, the pair formed a low-melting eutectic, a temporary liquid around growing crystal boundaries that let crystals rearrange.
- As heating continued the methylammonium chloride evaporated, leaving zinc concentrated at the boundaries, where it helped neutralize electronic defects.
- X-ray imaging showed the regions around crystal boundaries turning disordered and liquid-like during heating, then returning to an ordered state as the extra salt evaporated and growth ended.
- The group is now investigating other eutectic mixtures to control crystallization.
Why it matters
- contradiction Interesting Engineering's headline puts 26% on solar cell efficiency, but its text gives 24% to 26% for solar cells and LEDs together, so 26% is not safe to quote as the solar cell figure.
- constraint The durability evidence in the report is one continuous lamp-light test on solar cells, so any lifetime claim built on this paper needs data from elsewhere.
- capability Because the additives worked with the chemistries the team examined, other labs can try the same zinc bromide and methylammonium chloride pair on their own recipes.
The report gives no retained fraction for its durability test. Interesting Engineering reports that the solar cells "retained most of their initial efficiency" [3] in a test that ran 1,344 hours [13]. It does not state that fraction or the area of the devices tested.
The team changed how the film crystallizes. Perovskite films typically hold many small crystals, and defects at the boundaries between them cost energy and performance [8]. The report adds that the problem grows with panel size, because holding efficiency across a larger area is difficult [9]. In our view that makes the lamp-light test a check on the new films.
Connor Dolan, a co-first author and PhD alumnus of Fenning's lab [12], said, "Perovskites made with the eutectic-forming additives had the longest-lasting electron-hole pairs ever reported for any direct-bandgap semiconductor, which speaks to the promise of this approach," [16]. The time those pairs survive before recombining helps indicate how well a material can support solar energy conversion [17]. The measurement describes the film as made; for aging, the evidence is the eight-week test.
The team also reports breadth. "It seemed like everything we tried worked!" Dolan said [14]. The report says the method worked with the chemistries the team examined [15]. The researchers also want to know why the solid-liquid-solid change happens at the same temperature [11]. We'd expect any team setting a heating profile for a larger panel to want that answered first.
To place this paper on a roadmap, we'd draw a two-by-two. One axis is device size, small cell or full panel. The other is exposure, eight weeks of simulated sunlight or field conditions. The paper fills the lamp-light cell [3]. The size row depends on the area the authors used, and that is the first thing to ask them for. Only a result in the full-panel, field-exposure cell should move a production date. A result in any other cell supports something smaller: asking for the retained percentage and trying the additive mixture on your own film recipe [5].
What to watch
- Whether the authors publish the retained efficiency as a percentage, along with the area of the devices in the eight-week test.
- Results from the other eutectic mixtures the group is now investigating.
- Whether the additive route holds its efficiency when films are made at panel scale, where the report says uniformity gets harder.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence42
- Adoption
- Insufficient
- Hype gap+25
- Incentives
- Insufficient
- Confidence45
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
A team co-led by researchers at UC San Diego used a crystallization-control approach on perovskite-based solar cells and light-emitting diodes; the devices achieved efficiencies of around 24 percent to 26 percent, among the higher values reported for perovskite devices.
ReportedSupportedSource: Interesting Engineering report on the study2 sources— create a free account to open themView cited source - [2]
The report's headline reads: US scientists grow better perovskite crystals, boost solar cell efficiency to 26%.
ReportedSupportedSource: Interesting Engineering headline2 sources— create a free account to open themView cited source - [3]
Solar cells made using the technique retained most of their initial efficiency after eight weeks of continuous operation under simulated sunlight.
- [4]
Researchers led by David Fenning, professor of chemical and nano engineering at UC San Diego, worked with colleagues from Princeton University and Sungkyunkwan University in South Korea.
- [5]
The team added zinc bromide and methylammonium chloride to the solution used to produce a halide perovskite; when heated, the additives formed a low-melting eutectic that created a temporary liquid around growing crystal boundaries, allowing the crystals to rearrange into a more orderly structure.
- [6]
As heating continued, methylammonium chloride evaporated, leaving zinc concentrated around the crystal boundaries, where the remaining zinc helped neutralize electronic defects.
- [7]
X-ray imaging showed the regions around crystal boundaries became disordered and liquid-like during heating before returning to an ordered state as the extra salt evaporated and crystal growth ended.
- [8]
Perovskite films typically contain many small crystals; defects at the grain boundaries between neighboring crystals can cause energy losses and reduce device performance.
- [9]
The problem becomes more significant when manufacturers attempt to produce larger solar panels, where maintaining efficiency across a greater area is difficult.
- [10]
The team is now investigating other eutectic mixtures to better control crystallization.
- [11]
The researchers are interested in understanding why the solid-liquid-solid transformation occurs at the same temperature.
- [12]
Connor Dolan is a study co-first author and a chemical and nano engineering PhD alumnus from Fenning's lab.
- [13]
Eight weeks of continuous operation is 1,344 hours.
- [14]
"It seemed like everything we tried worked!"
ReportedInsufficientSource: Connor Dolan, study co-first author, quoted by Interesting EngineeringView cited source - [15]
The researchers tested the method across different perovskite compositions and found that it worked with the chemistries they examined.
- [16]
"Perovskites made with the eutectic-forming additives had the longest-lasting electron-hole pairs ever reported for any direct-bandgap semiconductor, which speaks to the promise of this approach,"
ReportedInsufficientSource: Connor Dolan, study co-first author, quoted by Interesting EngineeringView cited source - [17]
The time electron-hole pairs survive before recombining helps indicate how effectively a material can support solar energy conversion.
Sources
1 independent publisher whose own reporting we read for this story.
- interestingengineering.comUS scientists grow better perovskite crystals, boost solar cell efficiency to 26%
1 article · October 12, 2026
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