What if you could bottle sunshine and open it whenever you needed warmth?
Chemists at UC Santa Barbara have done something remarkably close. In a paper published in the journal Science in February 2026, Associate Professor Grace Han and her team unveiled a new material that captures sunlight, stores it within chemical bonds, and releases it as heat on demand — no batteries, no electrical grid required.
The material is a modified organic molecule called pyrimidone, and its design was inspired by an unlikely source: DNA. The pyrimidone structure is similar to a component found in DNA that undergoes reversible structural changes when exposed to UV light.
By engineering a synthetic version, the team created what they describe as a 'rechargeable solar battery.' When hit with sunlight, the molecule twists into a strained, high-energy shape — like a compressed spring. It stays locked in that shape indefinitely, until a trigger such as a small amount of heat or a catalyst snaps it back, releasing the stored energy as warmth.
'Think of photochromic sunglasses,' explains Han Nguyen, a doctoral student and the paper's lead author. 'You walk out into the sun, and they darken. Come back inside, and they clear. We're using the same idea — only instead of changing colour, we store energy, release it when needed, and reuse the material over and over.'
The numbers are impressive. The molecule boasts an energy density of more than 1.6 megajoules per kilogram — roughly double the 0.9 MJ/kg of a standard lithium-ion battery, and significantly higher than previous generations of molecular solar thermal storage.
The team demonstrated that the heat released was intense enough for practical applications like heating buildings or warming water. And because the molecule simply snaps between two shapes, the concept is inherently reusable and recyclable — no rare metals, no degradation over charge cycles.
'We cut everything we didn't need,' Nguyen says. 'Anything unnecessary, we removed to make the molecule as compact as possible.'
This technology, known as Molecular Solar Thermal (MOST) energy storage, has been a dream of chemists for decades. Previous attempts suffered from low energy density and instability. The UC Santa Barbara breakthrough solves both problems simultaneously.
While the technology is still being scaled up, the implications are enormous. Imagine buildings that absorb sunlight during the day and release warmth at night without any electrical infrastructure. Imagine remote communities with access to stored solar heat without needing battery supply chains.
A future where we truly capture the sun — not just its electricity, but its warmth — and carry it with us. That future just got a lot closer. ☀️