Thin-Wall Single-Crystal Gold Nanoelectrodes toward Advanced Chemical Probing and Imaging

Thin-wall metal ultramicro- and nanoelectrodes (UMEs/NEs), especially gold-based ones, are key probes for high-resolution electrochemical microscopy, biosensing, and nanoscale interfacial studies. Yet, their broader use remains limited by fragility, low detection sensitivity, and the lack of scalable fabrication methods. Here, we present a template-assisted, non-self-limited polyol-based growth strategy that realizes single-crystalline, thin-walled Au UMEs/NEs, as well as multifunctional probes, with high yield (>80%). The method provides precise control over electrode dimensions, from sub-100 nm to micron-scale radii while the massively parallel polyol growth step overcomes the key bottleneck in scalable nanoelectrode preparation by reliably producing long, continuous single-crystal metal cores. Structural and electrochemical characterization confirm twinned single-crystal Au cores, seamless Au/glass interfaces, and stable performance. Through direct comparison across radii, we show that smaller electrodes consistently exhibit higher surface reactivities, boosting chemical detection sensitivity. In scanning photoelectrochemical microscopy, these NEs achieve an illumination-dependent spatial resolution of ∼250 nm,