Characterization of copper electrodeposition in liquid phase electron microscopy

This application presents the Liquid-phase Transmission Electron Microscopy (LPTEM) technique, which integrates integrates liquid flow capabilities within microfabricated liquid cells, providing the means to study different processes in solution with sub-nanometer spatial resolution and sub-microsecond temporal resolution. Using this technique, it is now possible to visually study topics ranging from material science to life science.

There are several key advantages of this technique including:

    Control over liquid environment in a micro or nanoscale space
    Study dynamic processes in the liquid phase with nanoscale spatial resolution
    Determine the chemical composition in-situ
    Obtain electronic structure information

Materials and methods


Flow control


Liquid cell
The Stream Nano-Cell is a an advanced flow cell for controlling liquid environment within the microscope.

Sample holder
The in situ TEM Sample Holder provides the platform for connecting the pressure-based flow controller to the Nano-Cell.

FEI Titan 80-300.

Liquid sample
CuSO4 (20 mM) and KH2PO4 (10 mM) mixed aqueous solution.

Partial results

I. Control of the liquid flow and thickness within the microfluidic chamber

To demonstrate the high level of liquid control within the microfluidic chamber, the electrolyte was flowed into the window area and subsequently evacuated using the system described in the “Materials & Methods” part of the application note. […]

HAADF-STEM image of the window area of a liquid Nano-Cell at different environmental condition
Figure 2. HAADF-STEM images of the window area of a liquid biasing Nano-Cell at different environmental conditions:
(a) no liquid, (b) completely filled with liquid, (c) half evacuated and (d) no liquid.

II. Growth and morphology evolution of Cu dendrites

After flowing the electrolyte, cyclic voltammetry technique was used to study the electrodeposition of Cu. To do so, the electrolyte was injected using a flow rate of 1,7 µL/min, and voltage ranging from -0,70 V to 0,30 V was applied to the Pt electrode. Figure 3 shows a time series HAADF-STEM images illustrating the growth and etching process of Cu dendrites. We can directly observe the growth and morphology evolution of Cu dendrites. […]

Three series of HAADF-STEM
Figure 3. Time series of HAADF-STEM images illustrating the growth and etching process of Cu dendrites on the Pt
electrode by employing cyclic voltammetry scanning. In the experiments, incident electron flux was set ~50 e nm-2s-1,
and the liquid flow rate was 1.7 μL/min.

III. Microstructure and chemical composition analysis

Next, SAED analysis was performed. As a dry or thin liquid state is required for electron diffraction, the liquid is pushed out from the microfluidic chamber. Figure 4 a-d shows TEM images of (a) the Pt electrode and (c) the Cu dendrites on the electrode, and (b, d) the corresponding SAED patterns in the liquid phase. The polycrystalline nature of Pt electrode is confirmed by the SAED pattern (Figure 4 a, b). After the electrodeposition, the diffraction rings for polycrystal were resolved. The indication of 220 diffraction means at least a lattice resolution of ~1.28 Å or better can be obtained in the liquid thickness of ~100 nm.

Finally, the chemical composition of the obtained depositions are directly analyzed in the liquid phase. EDX elemental analysis (point, line, or area analysis) is conveniently performed. Figure 4e shows the HAADF-STEM EDX elemental mapping, displaying the spatial distribution of the Cu dendrites and the Pt electrode in the electrolyte, thus confirming the great functioning of this analysis.

TEM images of PT electrode & Cu dendrites & corresponding SAED patterns

Figure 4. TEM images of (a) the Pt electrode and (c) the Cu dendrites on the electrode, and (b, d) the corresponding SAED patterns in the liquid phase. (e) HAADF-STEM EDX elemental mapping, showing the spatial distribution of the Cu dendrites and the Pt electrode in the electrolyte.


We have demonstrated the use of a complete experimental system consisting in a TEM, advanced sample holder and flow cell, and high precision pressure-based flow controllers for the observation and characterization of copper electrodeposition in liquid phase transmission electron microscopy. The fundamental innovation of this design is the controlled flow. In fact, this design ensures that the liquid is forced to flow between the chips and across the imaging area, as this is the only route for the liquid to reach the outlet. By contrast, other commercially available and in-house fabricated liquid cells have a large volume which relies on diffusion to bring reactants to the viewing area. By directly interfacing the inlet tubing to the microfluidic channel on the chip, the direction and speed of the flow can be precisely controlled. Accordingly, the reactants are driven to the imaging area directly, and the cell can be flushed of reacted species. Finally, this configuration ensures that all the exiting liquid has experienced the same environment and temperature conditions. To the best of our knowledge, no other system either commercially available or custom-built, has employed a dual-chip configuration with on-chip channel.


1. De Yoreo, J. J. & Sommerdijk, N. A. J. M. Investigating materials formation with liquid-phase and cryogenic TEM. Nat. Rev. Mater. 1, (2016).

2. Hodnik, N., Dehm, G. & Mayrhofer, K. J. J. Importance and Challenges of Electrochemical in Situ Liquid Cell Electron Microscopy for Energy Conversion Research. Acc. Chem. Res. 49, 2015–2022 (2016).

3. Smeets, P. J. M., Cho, K. R., Kempen, R. G. E., Sommerdijk, N. A. J. M. & De Yoreo, J. J. Calcium carbonate nucleation driven by ion binding in a biomimetic matrix revealed by in situ electron microscopy. Nat. Mater. 14, 394–399 (2015).

4. Sugi, H. et al. Dynamic electron microscopy of ATP-induced myosin head movement in living muscle thick filaments. Proc. Natl. Acad. Sci. U. S. A. 94, 4378–4382 (1997).

5. Mirsaidov, U. M., Zheng, H., Casana, Y. & Matsudaira, P. Imaging protein structure in water at 2.7 nm resolution by transmission electron microscopy. Biophys. J. 102, L15–L17 (2012).

6. Peckys, D. B., Korf, U., Wiemann, S. & De Jonge, N. Liquid-phase electron microscopy of molecular drug response in breast cancer cells reveals irresponsive cell subpopulations related to lack of HER2 homodimers. Mol. Biol. Cell 28, 3193–3202 (2017).

7. Ahmad, N., Wang, G., Nelayah, J., Ricolleau, C. & Alloyeau, D. Exploring the Formation of Symmetric Gold Nanostars by Liquid-Cell Transmission Electron Microscopy. Nano Lett. 17, 4194–4201 (2017).

8. Wang, C. M. et al. In situ transmission electron microscopy and spectroscopy studies of interfaces in Li ion batteries: Challenges and opportunities. J. Mater. Res. 25, 1541–1547 (2010).

9. Williamson, M. J., Tromp, R. M., Vereecken, P. M., Hull, R. & Ross, F. M. Dynamic microscopy of nanoscale cluster growth at the solid-liquid interface. Nat. Mater. 2, 532–536 (2003).

10. van Omme, J. T. et al. Liquid phase transmission electron microscopy with flow and temperature control. J. Mater. Chem. C (2020) doi:10.1039/d0tc01103g

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