Researchers improve solar cell efficiency, stability

Purdue University researchers have created multifunctional ligands that improve the charge transfer, power conversion capability and long-term stability of perovskite solar cells.

By Steve Martin January 27, 2023
Ke Ma, a postdoctorate research assistant in Purdue’s Davidson School of Chemical Engineering, works on the fabrication of perovskite solar cells in front of a nitrogen-filled glove box. Ma and other Purdue researchers have developed conjugated ligands that improve the charge transfer, power conversion capability and long-term stability of perovskite solar cells. Courtesy: Vincent Walter, Purdue University

Energy efficiency insights

  • Purdue University researchers have created multifunctional ligands that improve perovskite solar cells.
  • Perovskite solar cells are lighter and thinner than silicon panels, reducing transportation and installation costs and they’re also more flexible.

Purdue University researchers have created multifunctional ligands that improve the charge transfer, power conversion capability and long-term stability of perovskite solar cells. Perovskite is a material that can be formed from different elements to have a variety of electrical, optical and physical characteristics. Perovskite can be manufactured as solar cells with simple techniques similar to printing newspapers; the techniques cost less and use less energy than those used to produce traditional silicon cells.

Perovskite solar panels are also much thinner and lighter than silicon panels, making the transportation and installation cost lower. They can be made lightweight and mechanically flexible and portable. Letian Dou, the Charles Davidson Associate Professor of Chemical Engineering in the Davidson School of Chemical Engineering, said perovskite solar cells have traits that limit their effectiveness.

“These solar cells lack an effective charge transfer and are unstable and vulnerable under prolonged light exposure, which often leads to degradation,” Dou said. “Poor stability means a shorter product lifetime, and consumers will need to replace a panel more frequently. Perovskite may not be stable for 25 years like silicon, but at least 10 years is required for successful commercialization. Replacing the panels also adds to the labor cost.”

Dou said traditional solar cells require a critical interface between perovskite and the organic charge collection layer. He said a molecular “glue” is needed, but conventional molecules block the current flow.

“Our conjugated ligands have a perfect fit into the perovskite crystal lattice and can help build a 2D-on-3D perovskite heterostructure, which further enhances the solar panel’s stability,” Dou said.

Dou and his team have tested the innovative ligands in their laboratory.

“We achieved near 25% power conversion efficiency with the ligands, compared to less than 20% without them,” Dou said. “We also improved the lifetime to more than 2,400 hours tested at 65 °C, which is four times longer than without the ligands.”

Dou and his team are taking additional steps to improve the ligands.

“We are working on new ligands to further what we’ve already achieved: more than 25% power conversion efficiency and more than 10,000 hours of operational lifetime,” Dou said. “We also are working to apply the ligands in larger-area solar modules. We look to achieve these goals within a year or so.”

– Edited by Chris Vavra, web content manager, Control Engineering, CFE Media and Technology, cvavra@cfemedia.com.


Author Bio: Steve Martin, Purdue University