New transparent solar cells could lead to ‘smart windows’ that generate electricity

23 Jul 2012

Transparent polymer solar cells produced by solution processing. Image by UCLA

Imagine a day when the windows in your home could generate electricity. Well, researchers at University of California, Los Angeles (UCLA) say they have developed a new type of transparent polymer solar cell that could lead to giving windows in homes and other buildings the ability to generate electricity while still allowing people to see through them.

The UCLA team has just had its research findings published in the nanoscience and nanotech journal ACS Nano.

The scientists and engineers involved in the study hailed from the California NanoSystems Institute (CNSI), the UCLA Henry Samueli School of Engineering and Applied Science and UCLA’s department of chemistry and biochemistry.

They are claiming to have come up with a new type of polymer solar cell (PSC) that produces energy by absorbing mainly infrared light, not visible light. As a result, the researchers said this would make the solar cells nearly 70pc transparent to the human eye.

They made the device from a photoactive plastic that converts infrared light into an electrical current.

Smart buildings of the future?

“These results open the potential for visibly transparent polymer solar cells as add-on components of portable electronics, smart windows and building-integrated photovoltaics and in other applications,” said Yang Yang, a UCLA professor of materials science and engineering, who also is director of the Nano Renewable Energy Center at CNSI.

He also said the new PSCs are made from plastic-like materials, making them lightweight and flexible. “More importantly, they can be produced in high volume at low cost,” said Yang.

The researchers at UCLA said they had another breakthrough by using silver nanowire composite films as the top transparent electrode in these solar cells. They described this transparent conductor as being comprised of a mixture of silver nanowire and titanium dioxide nanoparticles.

They said this electrode was able to replace the opaque metal electrode that had been used up to now.

But why is this so significant? Apparently, this composite electrode will allow the solar cells to be fabricated more economically by solution processing, achieving greater power-conversion efficiencies.

“We are excited by this new invention on transparent solar cells, which applied our recent advances in transparent conducting windows to fabricate these devices,” said CNSI director Paul Weiss.

Carmel Doyle was a long-time reporter with Silicon Republic