Tweak makes mass production of solar cells more sustainable

Researchers have demonstrated a technique for producing perovskite photovoltaic materials on an industrial scale, which will reduce the cost and improve the performance of mass-produced perovskite solar cells.

The technique is inexpensive, simple, energy efficient and should pave the way for the creation of perovskite solar cells. Perovskite is attractive for solar cells because it absorbs light very efficiently. This enables the creation of lightweight and flexible solar cells that can be integrated into a range of technologies, such as building or vehicle windows.

“In the lab, researchers are producing perovskite photovoltaic materials using a technique called spin-coating, which creates a thin film of perovskite on a substrate, but only on a small scale,” says Aram Amassian, corresponding co-author of a work article. and Professor of Materials Science and Engineering at North Carolina State University.

“We are talking about substrate samples that are only one or two square centimeters in size. However, people didn’t think it was possible to scale up spin-coating for manufacturing, using substrates several tens of square centimeters. Instead, people have opted for a variety of other methods. But these other methods produce perovskite photovoltaics that don’t perform as well as thin films made using spin-coating and have required significant research and development.

“What we’ve done here is demonstrate that you can produce perovskite photovoltaics on larger substrates using spin-coating by designing a co-solvent dilution strategy,” says co-author Michael Grätzel. correspondent of the article and professor at the Ecole Polytechnique Fédérale de Lausanne.

“In other words, you can increase photovoltaic production and preserve the excellent performance of almost any type of perovskite thin film produced using spin-coating.”

Historically, people believed that spin coating could not be used to produce perovskite photovoltaics on industrial scale substrates efficiently due to the nature of spin coating and perovskites.

Spin coating involves placing a liquid on the surface of a substrate and then spinning the substrate, so that the liquid material spreads over the surface. However, when perovskite is applied using this technique, the solvents that keep the perovskite in a liquid state do not evaporate quickly enough. This causes a lot of the perovskite to fly around the edges, which means a lot of the perovskite material is wasted. This also results in an uneven thickness of the perovskite on the surface, as well as some areas of the perovskite taking longer to dry than others. All of this is problematic from a manufacturing standpoint.

“Our approach addresses this challenge by introducing a co-solvent that allows the liquid perovskite to spread evenly and dry very quickly and evenly,” says Hong Zhang of École Polytechnique Fédérale de Lausanne, co-lead author of the item.

The new technique also significantly reduces waste and, by extension, reduces toxic byproducts associated with manufacturing perovskite photovoltaics.

“The beauty of this technique is that many industries are already using spin-coating technologies to produce all kinds of products,” says co-corresponding author Aldo Di Carlo, professor at the University of Rome Tor Vergata.

“Our work demonstrates that these existing technologies could be used to create perovskite solar cells. This could really speed up the production and deployment of perovskite solar panels and cells.

The collaborators of the demonstration project are already using the new technique to produce modules several tens of centimeters in diameter with excellent uniformity and performance.

“My team is now focused on using process automation and artificial intelligence to build on this work and further improve the efficiency, stability and sustainability of perovskite photovoltaics,” Amassian says. “We hope to work with public and private sector interests to find ways to implement this work and accelerate the development of perovskite solar cell technologies.”

The paper appears in the newspaper Nature Communication. Additional coauthors are from NC State and University of Rome Tor Vergata.

Support for the work came from the European Union’s Horizon 2020 research and innovation program, the Swiss National Science Foundation, the Italian Ministry of Economic Development and the United States Office of Naval Research.

Source: CN State