ELSA is a unique quasi in situ facility, being developed at TU Wien by CEST to cover the multiple research areas associated with the electrochemical technologies. This facility is dedicated to unravelling the surface and interface processes of thin films. This is a one-of-its kind facility, designed to understand the electrochemical surface/interface phenomena at real operating conditions and therefore, fully equipped to characterize the sample without exposing to air (as air exposure can alter the surface properties).
The unique features of ELSA include:
Research areas covered:
Central distribution chamber
ELSA will be connected to two electrochemical stations focused on:
Solid/liquid interface experiments: We are preparing an electrochemical (EC) chamber to carry out the quasi in-situ measurements on Solid/liquid interfaces. This chamber will be dedicated to electrolysis, CO2 reduction, corrosion, and recycling applications. The key component of an electrochemical setup is a cell, and it is well known that the cell designed for operando and in-situ clusters have some limitations. There is a trade off between the easy transfer of the working electrode and the geometry of the cell.
Herein, we are developing a unique three-electrode cell with ideal geometry to minimize the ohmic resistance. In addition to this, we are aiming to remove the organic impurities present in the electrolyte as their deposition at the surface of films complicates the surface/interface phenomena. Further details and images of electrochemical cell will be added soon.
Solid-electrolyte-interface (SEI) experiments: Second electrochemical chamber will be devoted for the cutting-edge research in the field of batteries. Further details will be added soon.
Ultra-High Vacuum (UHV) Kelvin Probe
Kelvin probe is a highly surface sensitive technique used to measure the work function of a material, defined by the maximum top three atomic layers. This technique is similar to atomic force microscopy (AFM) except being a non-contact technique. ELSA will be equipped with a UHV kelvin probe (Model- UHV KP020, KP Technology) to measure the work function of thin films before and after electrochemical measurements. As this technique is highly surface sensitive, we can determine surface changes (adsorption, surface reconstruction, defects, charge carrier trapping, corrosion etc.) occurring after exposure to electrolyte.
Scanning X-ray Photoelectron Spectroscopy (SXPS)
XPS technique is surface sensitive and used to determine the surface composition limited to the top few nm layer. It is based on the external photoelectric effect; the sample is irradiated with X-rays, which results in the emission of photoelectrons. The kinetic energy of the ejected photoelectrons reveals the elemental composition and electronic state of surface elements. That’s why this technique is also known as electron spectroscopy for chemical analysis (ESCA).
Model: PHI 5000 Versa Probe III SXPS
SXPS with above-mentioned specifications provides following information:
Auger Spectroscopy (AES)
ELSA will be equipped with AES, which is a complementary surface analysis technique. In AES technique, the sample is irradiated with a focused electron beam leads to the ejection of an inner shell electron. The vacancy of ejected electron is filled by an outer shell electron with emission of secondary X-ray. This secondary X-ray of energy equal to the energy difference between two orbitals leads to the ejection of another outer shell electron known as auger electron. The kinetic energy of auger electron is element specific and helps in evaluating the surface composition. The focused electron beam allows the analysis of ultramicroscopic area (5 nm or less). AES provides better spatial resolution over XPS as its probe beam is relatively 100 times smaller.
Model: Scanning Auger Nanoprobe (PHI 710)
ELSA will be equipped with a vacuum suitcase (≤ 10-10 mbar) to integrate the system with other CEST facilities. Therefore, we can transfer the sample from ELSA lab to CEST without exposing the surface to air.
PHI 5000 Versa Probe III, ELSA Lab, TU Wien
Scanning Auger Nanoprobe (PHI 710), TU Wien