Operando Analysis of Hot Electron Dynamics and Schottky Barrier Modulation in Hierarchical Au/WO₃Inverse Opal Photonic Crystal Micro-Chip for Enhanced Gas Sensing

Au nanoparticle-modified WO₃inverse opal photonic crystals (Au/WO₃IOPCs) exhibit exceptional NO₂sensing via synergistic hierarchical porosity, Au catalytic activity, and plasmonic hot electrons. A pioneering multimodal environmental operando microspectroscopy platform integrates photoconductive AFM, Kelvin probe microscopy, and in situ DRIFTS with computational modeling. This approach achieves atomic-scale spatiotemporal resolution of interfacial dynamics, directly revealing: (i) plasmonically generated hot electrons fluxing across the Au/WO₃interface to activate NO₂adsorption and modulate electron depletion layers under illumination and (ii) dynamic Schottky barrier reconfiguration at electrode junctions that quantitatively correlates environmental stimuli (gas concentration, photon flux, temperature) with resistance evolution. By bridging nanoscale charge transfer to device-level responses, the study establishes a transformative methodology for plasmon-enhanced photonic sensors while providing fundamental insights into interfacial processes, enabling knowledge-driven development of high-precision detectors with ultimate sensitivity and selectivity.