Molecularly Mediated Assembly of Metal Nanoparticles With Multifunctional Interfaces for Selective Detection of Small Gas Molecules

The rational engineering of nanostructured interfaces with tunable molecular functionality is central to advancing chemiresistive sensing materials. Here, we report a programmable sensing platform based on the molecularly mediated assembly of metal–nanoparticle thin films. Multifunctional ligands bridge nanoparticles into cohesive networks with tunable interparticle nanogaps that act as active sensing hubs. This architecture exploits synergistic interfacial interactions, wherein metal‐site adsorption governs selective gas recognition, ligand‐mediated specific or ionic interactions modulate local dielectric properties, and matrix partitioning controls background vapor uptake, collectively regulating charge transport through the film. The resulting sensing films exhibit high selectivity toward small gas molecules (CO, NH 3 , and H 2 O) with well‐defined, thermally activated chemiresistive behavior. Systematic studies of binary and ternary gas mixtures reveal predictable, additive response patterns and robust analyte discrimination using principal component analysis. These results establish a mechanistically guided framework for molecularly assembled nanoparticle chemiresistors, linking metal composition, ligand chemistry, and film architecture to addressable interaction pathways, for constructing programmable chemiresistive sensor arrays capable of detecting small gas molecules.