High-throughput, Picosecond Laser Interference-Patterned Doping of Thin Films for Spatially Resolved OER Screening

The development of efficient oxygen evolution reaction (OER) catalysts requires a detailed understanding of how structural and compositional modifications influence the catalytic performance. Here, we present a high-throughput platform to induce structural and chemical modification in Co3O4 thin films by combining direct laser interference patterning (DLIP) with picosecond-pulsed laser defect engineering in liquids (PUDEL) and spatially resolved electrochemical screening via scanning electrochemical cell microscopy (SECCM). This approach enables the generation of spatially varying surface modifications within a single experiment, including controlled film restructuring, defect formation, and compositional changes. Localized measurements reveal that the OER activity is maximized at moderate laser fluence, where film restructuring and compositional changes occur, while excessive fluence leads to ablation and reduced performance. Despite detectable Fe incorporation, activity trends are primarily governed by structural changes of the Co3O4 film. This work establishes DLIP-PUDEL combined with SECCM as a platform for rapid structure–activity correlation and accelerated electrocatalyst development.