Optically Transparent Carbon–Silicon Nitride Windows for Correlative Structural and Electrochemical Analysis of Nanomaterials

We report an optically transparent carbon electrode-silicon nitride (OTCE-SiN_<i>x</i>) window platform fabricated through clean-room microfabrication techniques. A wafer-scale fabrication process was implemented, which enabled a batch preparation of 2925 windows (100 × 100 μm) in user-friendly configurations. Application of OTCE-SiN_<i>x</i> windows is demonstrated in the high-resolution structural and nanoscale electrochemical characterization of nanocrystals by transmission electron microscopy (TEM) and electrochemical scanning probe microscopy. High-resolution TEM (HR-TEM) and aberration-corrected high-angle annular dark-field TEM (HAADF-TEM) were achieved for nanocrystals supported on the OTCE-SiN_<i>x</i>, with minimal background electron scattering or interference from the OTCE-SiN_<i>x</i>. Additionally, the stability of OTCE-SiN_<i>x</i> under prolonged voltammetric cycling was investigated. Scanning electrochemical cell microscopy (SECCM) revealed uniform nanoscale electrochemistry. Correlative electrochemical and electron microscopy on OTCE-SiN_<i>x</i> was demonstrated for the hydrogen evolution reaction (HER) at clusters of sub-10 nm Au nanospheres.