Innovation and Partnerships Office

Electrically Integrated Graphene on Silicon Nitride Liquid Flow Cells for High Resolution TEM 2014-129

APPLICATIONS OF TECHNOLOGY:
TEM for the study of electrochemical processes to advance

  • Catalysis
  • Battery and fuel cell technologies
  • Targeted drug delivery
  • Nanotechnology

ADVANTAGES:

  • Atomic resolution and contrast
  • Diminished alteration of samples
  • Simple and easy to use; little to no assembly by final user
  • Reusable

ABSTRACT:

A Berkeley Lab research team led by Paul Alivisatos and Alex Zettl has developed liquid flow cells providing unprecedented resolution and contrast in continuous flow Transmission Electron Microscopy (TEM). The cells can be used in sustained liquid flow and electric contact, facilitating the study and understanding of electrochemical processes at an atomic scale with diminished damage and alteration to samples. The fabrication method of the reusable cells guarantees little to no assembly on the part of the final user.

The innovative fabrication method developed by the Berkeley Lab research team combines silicon nitride and graphene to create a cell that successfully provides the advantages and avoids the shortcomings of each material. The flow region of the cell is a nanofluidic channel carved in a layer of silicon oxide between silicon nitride layers. The nanofluidic channel is accessible by both optical microscopy and e-beam microscopy due to the transparency of graphene and silicon nitride. The imaging region of the cell consists of patterned perforations of silicon nitride sealed by graphene to create viewports for electron imaging.

Currently, silicon nitride cells and graphene liquid cells lead the TEM field. Due their material properties, silicon nitride cells have low resolution and contrast and have undesirable charging and heating effects on samples. Graphene liquid cells offer electron transparency, since they provide atomic resolution and avoid charging and heating effects; however, they do not allow liquid flow or contacts for in-situ electrochemical studies. In contrast with the more commercially available silicon nitride cells, graphene cells require a high expertise level to fabricate. The Berkeley Lab liquid flow cells combine the advantages of silicon nitride and graphene cells while overcoming their deficiencies.

DEVELOPMENT STAGE: Proven principle

STATUS: Issued U. S. Patent #9,449,787. Available for licensing or collaborative research.

SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:

Atomic Resolution Transmission Electron Microscope Cell for Use with Liquid Samples, 2013-011

Transmission Electron Microscope Phase-contrast Enhancement, IB-2036

Automated Electron Microscopy Film Scanner, IB-1930

Hybrid Aperture Enhances Phase Contrast in Electron Microscopy, IB-2851

REFERENCE NUMBER: 2014-129