Engineered Molecule Stores Sunlight and Boils Water Months Later — On Demand

What if you could bottle sunlight and use it to heat your home in the dead of winter? Scientists have just gotten dramatically closer to making that a reality — with a molecule that stores solar energy in its chemical bonds for up to 3 years and releases enough heat to boil water in half a second.

How It Works

The molecule, derived from a compound called pyrimidone, belongs to an emerging field called molecular solar thermal (MOST) energy storage. Here's the elegantly simple concept:

1. The molecule absorbs sunlight and undergoes a structural transformation
2. In its new shape, energy is stored in strained chemical bonds — no batteries needed
3. When triggered by an acid catalyst, the molecule snaps back to its original form and releases all that energy as heat
4. It can then be recharged with light and reused

"We can recycle the molecule as fuel instead of burning it irreversibly," says Professor Grace Han at UC Santa Barbara. "Once you charge it with light, you don't have to worry about discharging like a battery."

Inspired by DNA Damage

In a twist of scientific creativity, the researchers drew inspiration from a process that normally damages DNA. Some DNA nucleobases absorb ultraviolet light to form pyrimidones — a well-known mechanism in UV skin damage. The team realized this same photochemical process could be engineered to store energy rather than cause harm.

Led by Han and Ken Houk at UCLA, they modified the reversible pyrimidone reaction to create the highest-performing molecular solar fuel ever reported. The results were published in Science.

Real-World Applications

The fuel solution can be mixed into water stored in a tank. When you need heat — in winter, at night, whenever — the catalyst triggers the release. Imagine charging your home heating system all summer by simply exposing a tank to sunlight, then using that stored heat throughout the cold months.