The Polymer Society of Korea

Abstract

Understanding and controlling molecular structure–function relationships at the single-molecule level is essential for designing advanced functional materials. Nanospectroscopy based on the scanning tunneling microscope (STM) accesses electronic and vibrational states with atomic resolution, revealing the origins of optical and electronic functions. We developed an integrated approach combining STM with tip-enhanced Raman spectroscopy, single-molecule photoluminescence, and ultrafast THz-pulse-driven exciton dynamics. These methods allow precise spatial and temporal control of molecular charge and reactivity. Using this platform, we clarified mechanisms of on-surface synthesis, including selective bond formation, C–C coupling vs. C–H activation, and polymerization vs. cyclization. Reaction pathways were steered by chemisorption direction and oxygen species. Our methodologies offer a spectroscopic platform beyond conventional techniques, with implications for molecular photonics and polymer design.