Researchers at Osaka University, Japan, are speeding up research on materials suitable for solar cells with a robotic system that automates experimental and analytical processes.

As solution-processed inorganic solar cells are manufactured with less toxic and Earth-abundant elements, they are emerging as viable alternatives to lead-halide perovskite solar cells. However, the range of elements and process parameters to be assessed impede their rapid development. Schematic of the automated measurement system. Source: Akinori Saeki/Osaka UniversitySchematic of the automated measurement system. Source: Akinori Saeki/Osaka University

The researchers devised a robotic measurement system to speed up the discovery and assessment of ideal materials by conducting photoabsorption spectroscopy, optical microscopy and time-resolved microwave conductivity analyses. As reported in the journal ACS Au, the robot was used to evaluate 576 thin-film semiconductor samples composed of varying blends of cesium, bismuth, tin and iodine.

The samples tested in were all made from a varying blend of cesium, bismuth, tin and iodine. They were also annealed at different temperatures and treated with different organic salt additives. The data generated by the robotic system was examined by application of machine learning to further characterize the material, gauge accuracy of the results and further improve process automation.

Initial findings are promising, as the measurement process has been demonstrated to be both fully automated and highly accurate, allowing work to be completed in one-sixth of the usual time needed. The automated system streamlines the task of identifying efficient and non-toxic solar materials.

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