Engineered molecule stashes enough sunlight to boil water months later
DNA-inspired pyrimidone sets capacity record for storing solar thermal energy in bonds
by Prachi Patel
The latest chemistry news, including important research advances, business and policy trends, chemical safety practices, career guidance, and more.
Solar panels are a foolproof way to harness sunlight for electricity on the cheap. But capturing and storing the sun’s heat energy is not easy.
Researchers have now created an organic molecule that stores a record amount of photon energy in its chemical bonds and releases it as heat on demand (Science 2026, DOI: 10.1126/science.aec6413). The molecule, derived from the aromatic compound pyrimidone, is water-soluble and can store energy for up to 3 years. When triggered by an acid catalyst, the material releases enough heat to bring water to a boil in 0.5 s. It can then be recharged with light and reused.
“We can recycle the molecule as fuel instead of burning it irreversibly,” as is done, for example, with natural gas and other fuels, says Grace Han, a chemistry professor at the University of California, Santa Barbara. “Once you charge it with light, you don’t have to worry about discharging like a battery.” The fuel solution can be mixed into water stored in a tank and triggered to release heat for buildings, she says.
The engineered pyrimidone stores a record 1.65 MJ of energy per kilogram, more than a lithium-ion battery and much more than any compound reported so far in the budding area of molecular solar thermal (MOST) energy storage. A MOST compound absorbs sunlight and undergoes transformation to a high-energy isomer. That form of the molecule stores energy in its strained bonds until a trigger makes it relax and revert to its original structure, emitting heat in the process.
Han, Ken Houk at the University of California, Los Angeles, and their colleagues drew inspiration from a photochemical process that damages DNA. Some DNA nucleobases absorb high-energy ultraviolet (UV) light to form pyrimidones. One such pyrimidone is known to form a stable high-energy isomer upon absorbing low-energy UV light but reverts to its original form when exposed to an enzyme.
The researchers modified this reversible pyrimidone by adding methyl groups on the molecule’s hexagonal ring. This engineered molecule is easy to synthesize and has excellent MOST properties, Han says. When it absorbs UV light at a wavelength of 300 nm, it forms a new bond that goes across the hexagon, forming two square units. An acid or heat breaks this bond and brings the isomer back to its original ring shape, releasing a lot of heat.
As a proof of concept, the team mixed 107 mg of the material in about 0.5 mL of water. They charged the material using UV light. When they added hydrochloric acid, the high-energy isomer released heat so fast that the water boiled in 0.5 s. Houk says that the team is now using detailed understanding of the chemistry to design even better MOST compounds.
Matthew Fuchter, who develops novel molecular systems at the University of Oxford, calls this “an exciting study [that] should seed much follow-on work.” The material currently requires UV light and takes a long time to charge, so engineering it to quickly charge using broad-spectrum sunlight will be necessary for real-world use, he says.
“I think the beauty of the work is in the simplicity of the bioinspired molecular design,” says Ivan Aprahamian, an expert on molecular switches and photochemistry at Dartmouth University. The pyrimidone is easy to make—the researchers made the material in gram quantities—which is important for practical use, he says. “Moreover, [it works] in water, which is important for water-based heating applications.”
Prachi Patel is a senior editor and physical sciences reporter at C&EN based in Pittsburgh.
2/3
FREE ARTICLES LEFT THIS MONTH
Get More
An editor’s selection of the C&EN stories that will continue to spark conversations in the week ahead
Privacy Policy
C&EN empowers those in and around the global chemical enterprise
Subscribe to C&EN
leftColumns exists: no
The Edge in Chemistry News
Copyright © 2026 American Chemical Society. All Rights Reserved.
Your email has been sent to
Article:
