Molecular Triboelectric Fingerprinting of Brominated Aromatics and Time-Resolved Monitoring of Suzuki-Miyaura Coupling.

Contact electrification at solid-liquid interfaces is highly sensitive to molecular electronic structure, yet its application to distinguish organic molecules and chemical transformations remains unexplored. Here, a systematic halogen substitution within brominated aromatic molecules is used to tune the interfacial electronic structure, enabling quantitative correlations among molecular structure, work function, surface potential, and triboelectric response. Molecularly modified polystyrene (PS) interfaces were fabricated by incorporating brominated aromatics (bromobenzene, 1-bromo-4-chlorobenzene, and 1-bromo-4-fluorobenzene) into a PS matrix coated on a copper wire. Systematic variation of the brominated aromatic substituents modulated the surface potential, work function, and triboelectric response of the PS interface. The molecular-dependent triboelectric response was correlated with changes in work function measured by ultraviolet photoelectron spectroscopy (UPS) and Kelvin probe force microscopy (KPFM) and computational studies. Furthermore, owing to the high volatility of bromobenzene, which limits stable triboelectric sensing, its conversion into the significantly less volatile biphenyl through the Suzuki-Miyaura coupling reaction was monitored using a contact-separation triboelectric system with copper oxide nanowires (CuO NWs). This work establishes a molecular framework linking interfacial electronic structure with triboelectric response, demonstrates self-powered monitoring of chemical transformations, and introduces a strategy for detecting highly volatile VOCs through chemical conversion into more stable products.