Scientists have created a smart window that not only brightens or darkens as needed -- it also acts like a battery.

At the Nanyang Technological University (NTU) in Singapore, researchers have developed a smart window that does not require any electricity and has a battery that can be recharged and utilized to power other devices.

Professor Sun Xiaowei, who led the research, highlighted that existing window solutions available to buyers are not smart enough to block or allow light when needed. Unlike the latest smart windows, existing window solutions do not have an integrated power source.

The latest window developed by NTU turns into a blue shade when there is bright light, reducing the penetration of light by 50 percent. The developers of the smart window suggest that the latest technology is extremely attractive as a "zero-sum consumption smart window."

"Buildings owners and even common households can reap energy savings right from the outset and over the long term. Developers who are looking at constructing environmentally-friendly green buildings will find our technology attractive for their building plans," said Professor Sun.

Professor Sun reveals that the window has a battery that is transparent, and it turns blue with the presence of oxygen in the electrolyte. The smart window has a liquid electrolyte positioned in between a couple of glass sheets, which has an indium tin oxide (ITO) coating.

The researchers say that ITO is normally used in television displays as a transparent conductive coating. One of the glass sheets also has a coating of a pigment called Prussian Blue, which gives the window a blue tone when fully charged. The other glass sheet has a thin aluminum foil strip attached to it.

Commonly used electrical cables connect the glass sheets. The break in the electric circuit causes a chemical reaction between the dissolved oxygen in the electrolyte and the Prussian Blue, which tints the glass blue. When the electric circuit is closed, the Prussian Blue changes to colorless Prussian White.

The researchers suggest that the technology is important as it saves lighting and cooling costs without the need for human intervention. Reduction in lighting and cooling also helps to reduce carbon emissions.

The study was published in the journal Nature Communications.