Quantitative Analysis on Interfacial Charges and Ions’ Speciation, and Identification of Interfacial Species Through Interfacial Waters’ Structure Revealed by Interface-specific Spectroscopy

Viewing interfacial molecular environments is of great importance to develop novel functional materials and to understand atmospheric, catalytic, and electrochemical reactions. Due to development in the lasing instruments and optical techniques in the past 20 years, the interface-specific vibrational spectroscopy, i.e., sum-frequency generation spectroscopy (SFG), has become a power tool to access such interfacial molecular structures. Here, I illustrate that heterodyne-detected SFG can provide quantitative interfacial property and molecular picture, and also can identify interfacial species from the interfacial waters’ structure with recent examples.