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Locking in Solar Power: How a Stronger Interlayer Boosts Perovskite Cell Durability

Daniel Morton — Mon, 05 Jan 2026 19:31:00 +0000

Locking in Solar Power: How a Stronger Interlayer Boosts Perovskite Cell Durability Daniel Morton Mon, 01/05/2026 - 12:31

New Molecular Designs Extend the Life and Efficiency of Next-Generation Solar Cells

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Posted on the RASEI website with permission and minor modifications from the piece published by David DeFusco on the UNC Chapel Hill Applied Physical Sciences Site here.

A new study published in Science led by researchers at UNC-Chapel Hill, with collaborators from the Renewable and Sustainable Energy Institute (RASEI), explains why perovskite solar cells—fast-rising rivals to traditional silicon panels—tend to break down under prolonged heat and sunlight, especially ultraviolet light, and reveals a promising strategy to dramatically slow that damage.

The work focuses on a thin “interlayer” that sits between the electrode and the perovskite material inside a solar cell. This layer is only a single molecule thick, but it plays an outsized role in how long the device lasts.

“These interlayers are meant to help charges move efficiently out of the perovskite and into the circuit,” said Chengbin Fei, first author of the study and a postdoctoral researcher in UNC’s Department of Applied Physical Sciences. “But we found that some of the same chemical features that make them useful can also cause long-term damage if they’re not tightly attached to the electrode.”

Many high-performance perovskite solar cells use interlayers based on phosphonic acids. These molecules stick to a transparent electrode made of indium tin oxide, or ITO, and help pull positive charges out of the perovskite. Until now, most researchers assumed these layers were harmless once installed. Fei and his colleagues discovered that this is not always true.

The researchers found that some of these tiny helper molecules aren’t firmly stuck to the solar cell’s surface. When the cell gets hot or sits in sunlight that includes ultraviolet rays, those that are loosely attached molecules can break free. Once that happens, they start interfering with the solar material itself. They trigger harmful changes inside the cell: key ingredients fall apart, iodine-related components react in damaging ways and lead turns into a form that no longer works properly. Over time, all of this damage adds up and causes the solar cell to produce less and less electricity.

“In simple terms, the acid part of these molecules can act like a slow poison,” said Fei. “At high temperatures and under UV light, it accelerates chemical reactions that the perovskite just can’t tolerate.”

To understand what was happening, the researchers used a range of techniques, including spectroscopy and X-ray measurements, to watch how the materials changed over time. They found that stronger acids caused faster damage and that UV light made the reactions much worse. This explained why devices that look stable at first can fail after hundreds or thousands of hours outdoors.

The key advance came when the researchers at UNC and the �� created a new version of this thin helper layer containing a combination of two molecules that sticks much more tightly to the electrode surface. Seth Marder, the senior author at the University of Colorado-Boulder and Director of the Renewable and Sustainable Energy Institute (RASEI) says “the molecule our team developed was designed to not only interact with the electrode surface but more strongly with its neighboring molecules. Consequently the molecules stay more securely in place, reducing the reactive parts that can break away and damage the solar material that is deposited on top ”. As a result, the layer still helps charges flow out of the cell, but it no longer triggers the damaging reactions that shorten the cell’s lifetime.

Simply put, “when the molecule is firmly locked onto the surface, it can’t wander into the perovskite and cause trouble,” said Fei. “That simple change makes a huge difference over time.”

Solar cells made with the new interlayer design showed striking improvements and met a key performance milestone. Under harsh test conditions—85 degrees Celsius, continuous bright light that included UV and constant operation—the devices ran for nearly 3,000 hours before losing just 10 percent of their efficiency. That level of durability has not been reported before for this type of perovskite solar cell.

The molecule our team developed was designed to not only interact with the electrode surface but more strongly with its neighboring molecules. Consequently the molecules stay more securely in place, reducing the reactive parts that can break away and damage the solar material that is deposited on top.
- Seth Marder

The researchers also scaled up their approach to small solar modules, closer to what might be used in real products. These “minimodules,” about the size of a postcard, reached power conversion efficiencies above 22 percent and kept working for more than 2,000 hours under the same stressful conditions, which is considered very high performance for this type of solar technology.

Jinsong Huang, senior author of the paper and UNC Louis D. Rubin Distinguished Professor, said the results address one of the most important barriers to commercialization. “Efficiency alone is not enough,” he said. “For perovskite solar technology to succeed outside the lab, it must survive heat, light and time. This work shows a clear chemical pathway to make that happen.”

Beyond improving one specific material, the study sends a broader message to the field. Tiny details at buried interfaces—places that are hard to see and easy to overlook—can control the lifetime of an entire solar module. By understanding and managing these details, researchers can design devices that last far longer.

“This study reminds us that stability is a chemistry problem as much as an engineering one,” said Wei You, a co-author of the study and UNC Cary C. Boshamer Distinguished Professor of Chemistry and Applied Physical Sciences. “Once you understand the chemistry, you can start to fix it.”

JANUARY 2026

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Layer-by-layer epitaxial growth of perovskite heterostructures with tunable band offsets

Daniel Morton — Fri, 14 Nov 2025 17:20:37 +0000

Layer-by-layer epitaxial growth of perovskite heterostructures with tunable band offsets Daniel Morton Fri, 11/14/2025 - 10:20

SCIENCE, 2025, 390, 6774, 716-721
November 2025

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Surface Passivation for Halide Optoelectronics: Comparing Optimization and Reactivity of Amino-Silanes with Formamidinium

Daniel Morton — Fri, 07 Nov 2025 18:17:31 +0000

Surface Passivation for Halide Optoelectronics: Comparing Optimization and Reactivity of Amino-Silanes with Formamidinium Daniel Morton Fri, 11/07/2025 - 11:17

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2025, 147, 46, 42918-42925

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Anomalous Stiffening of a Conjugated Polymer During Electrochemical Oxidation

Daniel Morton — Fri, 17 Oct 2025 17:33:25 +0000

Anomalous Stiffening of a Conjugated Polymer During Electrochemical Oxidation Daniel Morton Fri, 10/17/2025 - 11:33

ADVANCED FUNCTIONAL MATERIALS, 2025, e19980
October 2025

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Spin Interactions in Supramolecular Assemblies of Porphyrin Oligomer Radical Anions

Daniel Morton — Tue, 07 Oct 2025 23:37:06 +0000

Spin Interactions in Supramolecular Assemblies of Porphyrin Oligomer Radical Anions Daniel Morton Tue, 10/07/2025 - 17:37

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 2025, e202518425

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Symmetry Breaking Induced by Chiral Phosphonic Acids in a 2D Tin-Halide Perovskite

Daniel Morton — Mon, 29 Sep 2025 23:27:50 +0000

Symmetry Breaking Induced by Chiral Phosphonic Acids in a 2D Tin-Halide Perovskite Daniel Morton Mon, 09/29/2025 - 17:27

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2025, 147, 40, 36642-36649

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Polymeric microwave rectifiers enabled by monolayer-thick ionized donors

Daniel Morton — Fri, 19 Sep 2025 23:21:09 +0000

Polymeric microwave rectifiers enabled by monolayer-thick ionized donors Daniel Morton Fri, 09/19/2025 - 17:21

SCIENCE ADVANCES, 2025, 11, 38, eadv9952

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Atomic-Scale Electric Potential Landscape across Molecularly Gated Bilayer MoS2 Resolved by Photoemission

Daniel Morton — Mon, 08 Sep 2025 23:14:26 +0000

Atomic-Scale Electric Potential Landscape across Molecularly Gated Bilayer MoS2 Resolved by Photoemission Daniel Morton Mon, 09/08/2025 - 17:14

ACS NANO, 2025, 19, 36, 32693-32704

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Narrow-Band Electrochromism of Ferrocene-Substituted Rhodamine B

Daniel Morton — Tue, 29 Jul 2025 19:54:28 +0000

Narrow-Band Electrochromism of Ferrocene-Substituted Rhodamine B Daniel Morton Tue, 07/29/2025 - 13:54

CHEMISTRY OF MATERIALS, 2025, 37, 15, 5558-5568

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Electrolyte Immersion Increases Photoconductivity in a Model Polymer Photocathode

Daniel Morton — Mon, 28 Jul 2025 19:41:39 +0000

Electrolyte Immersion Increases Photoconductivity in a Model Polymer Photocathode Daniel Morton Mon, 07/28/2025 - 13:41

ACS ENERGY LETTERS, 2025, 10, 4019-4026

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