Production and detection of solvated electrons with atmospheric-pressure plasma jets

At the plasma-liquid interface, plasma electrons can dissolve in a liquid solution to form solvated electrons. Solvated electrons are a strong reducing agent and have applications in chemistry and plasma medicine. The Bartels & Go groups at the University of Notre Dame have produced and detected solvated electrons at a plasma-liquid interface using a direct DC discharge. However, little work exists on the production of solvated electrons by remote sources such as atmospheric pressure plasma jets (APPJs). We plan to implement the total internal reflection geometry of Rumbach, et al. [1] to measure solvated electron concentration produced by APPJs. Laser light is reflected off the underside of the water-plasma interface to probe the ~10nm layer in which electrons are solvated and lock-in detection is used to recover the modulated absorption signal. We present our design, preliminary measurements, and possible diagnostic improvements (e.g., cavity enhancement) in detecting and producing these solvated electrons with jet sources.

[1] Rumbach, P., Bartels, D. M., Sankaran, R. M., & Go, D. B. (2015). The solvation of electrons by an atmospheric-pressure plasma. Nature Communications, 6(1), 7248. https://doi:10.1038/ncomms8248