Liquid-Grown Perovskite Films Hit 26.5% Solar Efficiency and Record Low Defects

Those defects trap or destroy photogenerated charge carriers — the electrons and holes that carry current. The result is devices that lose performance and age faster than their raw material potential suggests.

How does the liquid trick fix it?

The team's solution borrows from metallurgy: the eutectic phenomenon, where a mixture of two substances melts at a far lower temperature than either component alone. The researchers combined methylammonium chloride (MACl) with a zinc halide (ZnX₂), two materials with relatively high individual melting points. Mixed together, the blend turns liquid at a much gentler temperature.

When the researchers warmed the perovskite film to around 100°C (212°F) — roughly the temperature of boiling water — the mixture sitting at the grain boundaries melted into a thin liquid layer. In liquid form, atoms diffuse about 10,000 times faster than in a solid. That speed lets small grains rapidly merge into larger, cleaner crystals with fewer defects.

The process is self-cleaning, too. MACl, which helps crystal growth, simply evaporates away during thermal annealing. The remaining zinc migrates to the grain boundaries and actively suppresses defects there. The result: films the authors describe as the highest quality reported to date for perovskite thin films, with surface quality comparable to the best passivated silicon.

One film, two devices

The efficiency headline isn't limited to solar power. The team built an LED with the exact same device architecture, and it hit an external quantum efficiency of 26.1% — a measure of how efficiently a device converts electrons into photons.

In other words, a single structure works both as a power generator that absorbs light and as a light emitter. Professor Shin framed the breakthrough in method terms: "This study is the world's first to develop a crystal-growth method based on a volatile eutectic mixture that fundamentally reduces defects in perovskites. Beyond realizing both a highly efficient solar cell and an LED within a single device architecture, the process requires no expensive specialized equipment."

He added that the approach should extend beyond solar cells and LEDs "not only in various optoelectronic devices, including displays and photodetectors, but also across the wider field of materials science."

Who did what

The study was jointly led by corresponding authors professor Shin, professor David P. Fenning of UC San Diego, and professor Dane W. deQuilettes of Princeton. Co-first authors are Nam, Dr. Jason J. Yoo of KRICT, and Dr. Connor J. Dolan of UC San Diego.

The paper appears as Jason J. Yoo et al., "Volatile eutectics to tailor crystallization for perovskite optoelectronics," Science (2026), DOI: 10.1126/science.aeb4554.

As always with lab-stage records, caveats apply: certified efficiency came in slightly below the lab measurement, at 25.9%, and long-term durability at scale remains the field's open question. But with no specialized equipment required and strong performance already shown over large areas, this liquid-assisted route marks a serious step toward commercial perovskite devices.