A recent study by Lawrence Berkeley National Laboratory (Berkeley Lab), Technische Universität München, EPFL and The Pennsylvania State University has found that solar materials manufacturing could be aided by a new instrument that uses two types of light ' invisible X-ray light and visible laser light ' to probe a perovskite material's crystal structure and optical properties as it is synthesized.
'When people make solar thin films, they typically have a dedicated synthesis lab and need to go to another lab to characterize it. With our development, you can fully synthesize and characterize a material at the same time, at the same place', said Carolin Sutter-Fella, a scientist at Berkeley Lab's Molecular Foundry.
The new instrument's highly intense X-ray light allows researchers to probe the perovskite material's crystal structure and unveil details about fast chemical processes. For example, it can be used to characterize what happens in the second before and after a drop of a solidifying agent transforms a liquid precursor solution into a solid thin film.
At the same time, its laser can be used to create electrons and holes (electrical charge carriers) in the perovskite thin film, allowing the scientists to observe a solar material's response to light, whether as a finished product or during the intermediate stages of material synthesis.
'Equipping an X-ray beamline endstation with a laser empowers users to probe these complementary properties simultaneously,' explained Sutter-Fella.
This combination of simultaneous measurements could become part of an automated workflow to monitor the production of perovskites and other functional materials in real time for process and quality control.
The beamline endstation allows researchers to observe what happens during synthesis, and in particular during the first few seconds of spin coating, a critical time window during which the precursor solution slowly begins to solidify into a thin film.
First author Shambhavi Pratap, who specializes in the use of X-rays to study thin-film solar energy materials, played a critical role in developing the instrument as an ALS doctoral fellow. She recently completed her doctoral studies in the Müller-Buschbaum group at the Technical University of Munich. 'The instrument will allow researchers to document how small things that are usually taken for granted can have a big impact on material quality and performance,' Pratap said.
'To make reproducible and efficient solar cells at low cost, everything matters,' Sutter-Fella said. She added that the study was a team effort that spanned a wide range of scientific disciplines.
'We know that the research community is interested in using this new capability at the ALS,' she said. 'Now we want to make it user friendly so that more people can take advantage of this endstation.'
