Researchers at the Massachusetts Institute of Technology (MIT) have created a material that can collect the sun’s radiant energy and release it as heat hours or days later.
The material takes the form of a transparent polymer that can be applied to surfaces such as window glass or clothing.
It is made of chemical compounds called azobenzenes, which contain molecules that can remain stable in two possible configurations.
When exposed to sunlight, the light energy kicks the molecules into their charged state. They then stay that way until exposed to a stimulus that returns them to their original shape, giving off a burst of heat in the process.
MIT graduate student Eugene Cho said making the new material required a two-step process that was "very simple and very scalable".
Tests have been carried out that suggest the transparent material could be used to quickly de-ice car windshields. MIT professor Jeffrey Grossman said: "We did tests to show you could get enough heat to drop ice off a windshield."
German car company BMW, a sponsor of the research, is interested in this application.
Ted Sargent, university professor at the University of Toronto, said: "The research is a major advance towards the practical application of solid-state energy-storage and heat-release materials from both a scientific and engineering point of view."
Image: A close up of the solar thermal fuel polymer film, comprised of three distinct layers (MIT)