New technique paves the way for perfect perovskites

The Advanced Light Source has a new technique that shows what happens in the second before and during solidifying agents. This transforms the liquid precursor solution into a perovskite-solar material. Credit: Berkeley Lab
A new, exciting solar material called organic-inorganic perovskites could help the U.S. reach its solar ambitions and decarbonize its power grid. Perovskite solar material is a thousand times thinner than Silicon and can be modified to react to different colors by changing their composition.

Hybrid perovskite solar material is typically made from organic molecules like methylammonium or inorganic metal halidides like lead iodide. They have a higher tolerance for defects in the molecular structure and absorb visible sunlight more effectively than silicon, which is the industry standard.

These qualities combine to make perovskites promise active layers in photovoltaics (technologies which convert light into electricity), as well as other electronic devices that respond or control light, such light-emitting diodes, detectors, lasers, and light-emitting diodes.

"Perovskites have great potential to greatly expand solar power but they have not been commercialized yet because of their reliable synthesis, long-term stability and lack of commercialization," Carolin SutterFella, a scientist at Molecular Foundry (Berkeley Lab), said. "Now, the path to perfect perovskites might soon be possible."

Sutter-Fella co-leads a Nature Communications study that suggests that a new instrument could help in the manufacture of solar materials. It uses visible laser light and lightinvisibleX-ray light to probe the crystal structure and optical properties of a perovskite as it is synthesized.

"When making solar thin films, people typically have their own synthesis labs and must travel to another lab to analyze it. She said that with our technology, it is possible to fully synthesize and characterize the material simultaneously at the same location.

Credit: Lawrence Berkeley National Laboratory

Sutter-Fella assembled a team of top engineers and scientists to outfit an X-ray beamline station with a laser from Berkeley Lab's Advanced Light Source.

Researchers can examine the crystal structure of perovskite materials and learn more about chemical reactions using the new instrument's intense X-ray radiation. It can also be used to determine what happens after a drop or two of a solidifying agent transforms liquid precursor solution into a thin film.

It can also be used to generate electrons and holes (electrical charges carriers) in the thin perovskite film. This allows scientists to observe the response of a solar material to light, either as a finished product, or during intermediate stages.

Sutter-Fella explained that by equipping an X-ray beamline station with a laser, users can simultaneously probe these complementary properties,"

The combination of simultaneous measurements can be used to automate the monitoring of production of perovskites in real-time for quality control and process control.

Spin coating is a cost-effective method for making perovskite films. It doesn't require complicated chemical setups or expensive equipment. The case for perovskites is even more compelling when you consider how energy-intensive manufacturing silicon into a solar device requires a temperature of approximately 2,732 degrees Fahrenheit. Perovskites, on the other hand, can be processed at room temperature up to 302 degrees Fahrenheit.

Spin coating is a cost-effective method of making perovskite films. It doesn't require complex chemical setups or expensive equipment. Shambhavi Pratap

Researchers can observe the synthesis process from the beamline endstation, which allows them to see the precursor solution solidify slowly into thin films.

Shambhavi Pratap is the first author. She specializes in the study of thin-film solar-energy materials using X-rays. As an ALS doctoral fellow, she played a crucial role in the development of the instrument. She completed her doctoral studies at the Technical University of Munich's Mller-Buschbaum Group.

Pratap stated that the instrument would allow researchers to see how seemingly small changes can have a significant impact on material quality or performance.

Sutter-Fella stated that everything is important in order to make solar cells that are reproducible and cost-effective. She said that the team effort involved a broad range of scientific disciplines.

This is the latest chapter of a body that Sutter-Fella has been working on since 2017.

She stated that "we know that the research community was interested in this new capability at ALS." "Now, we want it to be user-friendly so that more people can benefit from this endstation."

Continue reading to find out more about a new roadmap for better-performing solar energy cells

Further information: Shambhavi Pratap and colleagues, Out-of–equilibrium processes during crystallization organic-inorganic rovskites during spin coating Nature Communications (2021). Information from Nature Communications Shambhavi Pratap et. al., Out-of–equilibrium processes during crystallization organic-inorganic PErovskites during spin coating. (2021). DOI: 10.1038/s41467-021-25898-5