Application of Electrospray Droplet Impact (EDI) to Surface Science

Abstract

In Electrospray Droplet Impact (EDI), the charged liquid droplets formed by ambient electrospray are introduced through an orifice into vacuum, accelerated by 10 kV and impact the samples prepared on the metal substrate. The secondary ions are detected by an orthogonal-type time-of-flight mass spectrometer. EDI can afford soft ionization/desorption for various kinds of real-world samples such as biological tissues, dyes, pigments, synthetic polymers, and inorganic materials with no special sample preparation. EDI is capable of atomic- and molecular-level etching with leaving little damage on the etched surface. Moreover, the useful yield (total ions generated divided by the total atoms or molecules desorbed) was found to be larger than 10^-2. Due to these unique natures, EDI may be promising for the next-generation nano-scale 3D imaging.