The Department of Materials and Environmental Chemistry (MMK) in the Arrhenius Laboratory at Stockholm University (SU) conducts research in the fields of materials chemistry and solid-state chemistry, amongst others. The research has been largely dependent on Electron Microscopy (EM), which has been exploited and developed at the department continuously since 1974.


EM at MMK has traditionally used various techniques in imaging and diffraction together with analytical features for the study of a wide range of materials. Some specialized areas of research at MMK are the synthesis and processing of inorganic as well as bio-based materials, the study of structure and properties and the development of electron crystallography methods. Materials presently studied comprise mesoporous crystals, nanoparticles and nanostructured materials, soft and biomaterials, etc; The typical compositions of the materials span from zeolites, natural minerals and synthetic oxides to carbon, ceramics, alloys, and semiconductors and also nanocellulose and proteins. These materials find applications in batteries, supercapacitors, fuel cells, catalysts, sensors, biomedicine,  and ...


The basis for EMC is several well-equipped high quality analytical transmission electron microscopes (TEM) and scanning electron microscopes (SEM) as well as two skilled instrument responsible. The TEMs have modern high performance cameras and a number of sample holders of various kinds. At EMC there also are instruments for sample preparation. This well-equipped EMC-lab was made possible by a generous donation from the Knut and Alice Wallenberg (KAW) Foundation for a joint application from SU and KTH for more than 10 years ago (main applicant Osamu Terasaki). Further strengthening of the EM-based research was also possible thanks to the KAW-financed project 3DEM-NATUR (main applicant Xiaodong Zou). As important as the instrument are the two skilled application specialists, Kjell Jansson and Cheuk-Wai Tai, who train the users of the facility, take care of the instruments and advice the users on methodologies for scientific research. Their employment is possible due to a strong support from MMK and the Faculty of Sciences at SU.

 

The success of EMC during the years is reflected in the large number of publications involving EM. The level of maturity of the EMC has resulted in MMK and SU together deciding to purchase and finance a new state-of-the-art double aberration corrected microscope. The chosen microscope, a Thermo Fisher Scientific™ Themis Z with a number of sample holders, was delivered in Spring 2018.

 

Themis Z at EMC, Stockholm University

Aberration-corrected transmission electron microscope Thermo Fisher Scientific™ Themis Z at the Electron Microscopy Center (EMC), Department of Materials and Environmental Chemistry (MMK), Stockholm University will be inaugurated on 20th May 2019. Themis Z at EMC is equipped with probe and image aberration correctors, providing excellent imaging capability at atomic resolution in both high-resolution STEM (scanning transmission electron microscopy) and TEM. The microscope currently can operate at accelerating voltages of 60 kV, 200 kV and 300 kV. Themis Z at EMC delivers spatial resolution ≤ 60 pm in both TEM and STEM at 300 kV. A Gatan Oneview camera with in-situ option is present for fast acquisition of high quality TEM images (max 300 frames per second). A range of STEM detectors are present for collecting signals simultaneously to form different images. A four quadrant Super-X EDX detector enables high analytical capability down to atomic scale. A Gatan imaging filter (Quantum ER) for electron energy loss spectrometer (EELS) and energy-filtered imaging attached to Themis Z provides fast spectrum (1000/sec) acquisition and it is capable to collect spectra in both low and high-energy regimes simultaneously. The field-emission electron gun is equipped with a monochromator; the use of such an electron probe in analytical studies with EELS provide high energy resolution (<0.2 eV) providing the possibility to measure band-gap of materials, surface plasmons, valence band structures, chemical bond information etc. at the atomic scale. Automated tomography acquisitions in TEM, STEM and STEM-EDX are also possible. A number of sample holders are present for imaging, analytical studies, tomography and in-situ heating/cooling experiments.


EMC is a node of CEM4MAT, the initiative to open up and increase the collaboration between the TEM facilities in the Stockholm-Uppsala region.

 

The specific goal of the Electron Microscopy Centre is to build a scientifically open and active centre with a state-of-the-art EM facility at Stockholm University (SU).