SELECT PUBLICATIONS

Electron-Water Interactions and Implications for Liquid Cell Electron Microscopy

Nicholas M. Schneider, Michael M. Norton, Brian J. Mendel, Joseph M. Grogan, Frances M. Ross, and Haim H. Bau

Liquid cell electron microscopy enables direct in situ imaging of processes in liquids and objects suspended in liquids with nanoscale resolution. However, the irradiating electrons affect the chemistry of the suspending medium, typically an aqueous solution, producing molecular and radical products such as hydrogen, oxygen, and hydrated (solvated) electrons. These may impact the imaged structures and phenomena. A good understanding of the interactions between the electrons and the irradiated medium is necessary to correctly interpret experiments, minimize artifacts, and take advantage of the irradiation. We predict the composition of water subjected to electron irradiation in the electron microscope. We re-interpret available experimental data, such as beam-induced variations in pH and colloid aggregation, in the light of our predictions, and show new observations of crystallization and etching as functions of dose rate, resolving conflicting reports in the scientific literature. We make our computer code available to readers. Our predictive model is useful for designing experiments that minimize unwanted beam effects; extending liquid cell microscopy to new applications; taking advantage of beam effects for nanomanufacturing such as the patterning of nanostructures; and correctly interpreting experimental observations.  Additionally, our results indicate that liquid cells provide a new tool to study radiolysis effects on materials and processes.

Schneider, N.M., Norton, M.M., Mendel, B.J., Grogan, J.M., Ross, F.M. and Bau, H.H., “Electron-Water Interactions and Implications for Liquid Cell Electron Microscopy,” J. Phys. Chem. C, vol. 118, no. 38, pp. 22373–22382, Sep. 2014.

 

Bubble and Pattern Formation in Liquid Induced by an Electron Beam

Joseph M. Grogan, Nicholas M. Schneider, Frances M. Ross, and Haim H. Bau

Liquid cell electron microscopy has emerged as a powerful technique for in situ studies of nanoscale processes in liquids. An accurate understanding of the interactions between the electron beam and the liquid medium is essential to account for, suppress, and exploit beam effects. We quantify the interactions of high energy electrons with water, finding that radiolysis plays an important role, while heating is typically insignificant. For typical imaging conditions, we find that radiolysis products such as hydrogen and hydrated electrons achieve equilibrium concentrations within seconds. At sufficiently high dose-rate, the gaseous products form bubbles. We image bubble nucleation, growth, and migration. We develop a simplified reaction-diffusion model for the temporally and spatially varying concentrations of radiolysis species and predict the conditions for bubble formation by H2. We discuss the conditions under which hydrated electrons cause precipitation of cations from solution and show that the electron beam can be used to “write” structures directly, such as nanowires and other complex patterns, without the need for a mask.

Grogan, J.M., Schneider, N.M., Ross, F. M., and Bau, H.H., “Bubble and Pattern Formation in Liquid Induced by an Electron Beam,” Nano letters 14 (1), 359-364, 2014.

 

In-Situ Electron Microscopy of Electrochemical Deposition, Dendrite Growth, and Etching 

Nicholas M. Schneider, Jeung Hun Park, Joseph M. Grogan, Suneel Kodambaka,Daniel A. Steinhart, Frances M. Ross, and Haim H. Bau

Recent advances in in situ liquid cell electron microscopy allow us to image the evolution of electrochemical deposition and stripping in real time with nanoscale resolution while controlling the current or potential during the process. Here we show a selection of frames from in situ electron microscopy video during the electrochemical deposition and stripping of copper in an acidified copper sulphate solution. 

 

 

Schneider, N.M., Park, J.H., Grogan, J.M., Kodambaka, S., Steingart, D.A., Ross, F.M. and Bau, H.H., “In-Situ Electron Microscopy of Electrochemical Deposition, Dendrite Growth, and Etching,” J. Heat Transfer, vol. 136, no. 8, p. 080910, Aug. 2014

PUBLICATIONS

BOOK CHAPTERS

  • Schneider, N.M., “Electron beam effects in liquid cell TEM and STEM,” Liquid Cell Electron Microscopy, Cambridge University Press, Late 2015

PUBLICATION IN PREPARATION

  • Schneider, N.M., Park, J.H., Grogan, J.M., Steingart, D.A., Kodambaka, S., Bau, H.H., and Ross, F.M., “Direct Nanoscale Observation of the Transition to Diffusion Limited Electrodeposition,” (Journal Article in Preparation)
  • Norton, M.M, Schneider, N.M., Ross, F.M., and Bau, H.H., “Growth and Transport of Sub-Micron Bubbles in a Wedge Geometry,” (Journal Article in Preparation)

INVITED TALKS

  • Schneider, N.M., "Liquid cell transmission electron microscopy for analysis of solid/liquid interfaces,” TAILored surfaces in Operando conditions: Structure and Reactivity, 2016 April 1, Fontainebleau, Paris, France.
  • Schneider, N.M., Park, J.H., Grogan, J.M., Kodambaka, S., Steingart, D.A., Ross, F.M. and Bau, H.H., “Visualizing In Situ Electrochemical Deposition and Dendrite Growth with the Nanoaquarium,” Materials Research Society Fall Meeting, 2013, Boston, MA. (Selected as part of the first MRS Monthly Webinar on “In Situ Electron Microscopy”, Video Available) 
  • Schneider, N.M., “Liquid Cell Electron Microscopy with the nanoAquarium: Radiation and Electrochemistry,” Villanova University, VCASE Lecture Series, 2014 October 24, Villanova, PA.
  • Schneider, N.M., “Radiation Chemistry in Liquid Cell Electron Microscopy,” Center for Nanophase Materials Sciences, Oak Ridge National Lab, Advanced Electron Microscopy Workshop: Aberration-Corrected STEM Imaging, Spectroscopy, and In Situ Microscopy, 2014, September 18-19, Oak Ridge, TN.
  • Schneider, N.M.“In Situ Liquid Cell Electron Microscopy with the NanoAquarium: A Study in Electrochemistry and Radiation Chemistry”, University of Pennsylvania, Mechanical Engineering and Applied Mechanics Department Seminar, 2014 June 17, Philadelphia, PA. (VIDEO)
  • Schneider, N.M., "In Situ Electron Microscopy of Liquids with the NanoAquarium", RIT Mechanical, Chemical and Biomedical Engineering Seminar, 2013 October 10, Rochester, NY.
  • Schneider, N.M., Keynote Address presented at: RIT’s 2013 Undergraduate Research Symposium, 2013 August 2, Rochester, NY. (Video Available)

 

PRESENTATIONS AND TALKS