X-ray unveils the creation process of materials on several length scales

Nanostructuring often makes materials very powerful in many applications. Some nanomaterials take on the desired complex structures independently during their creation process. Scientists from the University of Hamburg, DESY, ESRF and the Ludwig Maximilians University in Munich have studied the formation of cobalt oxide crystals just a few nanometers in size and how they assemble, while they are still being formed. The results are published in Nature Communications.

Nanomaterials have special properties that make them more effective than conventional materials in various applications. In sensors and catalysts (in green energy production, such as water splitting into energy-rich hydrogen and oxygen) the important chemical processes happen at the surface. Nanostructured materials, even in small amounts, provide a very large surface and are therefore suitable for this kind of applications.

Further potential arises due to the variety of shapes and material combinations that are conceivable on the nanoscale. However, establishing the exact shape of these nanostructures can be a tedious process. Researchers focus on nanocrystals that independently form complex structures without any external influence, for example by sticking together (assembling). This increases their effectiveness in important technological applications, such as green energy generation or sensor technology.

“Often nanoparticles arrange themselves independently, as if following a blueprint, and take on new shapes,” explains Lukas Grote, one of the main authors of the study and scientist at DESY and the University of Hamburg. “Now, however, we want to understand why they are doing this and what steps they go through on the way to their final form. That is why we follow the formation of nanomaterials in real time using high-intensity X-rays. ” For some of the experiments, the researchers used the European Synchrotron Radiation Facility (ESRF) and DESY’s synchrotron radiation source PETRA III.

Read more on the ESRF website

Image: X-rays from a synchrotron radiation source are both attenuated (absorbed) and deflected (scattered) by matter. Depending on which of these interactions is measured with a certain X-ray technology, conclusions can be drawn about different stages of the development process of a nanomaterial. If you combine both X-ray absorption and X-ray scattering, you can decipher all the steps from the starting material (left) to the fully assembled nanostructures (right).

Credit: Nature Communications

Researchers watch nanomaterials growing in real time

For the first time, a team of scientists including from DESY has succeeded in capturing in real time the first few milliseconds in the life of a gold coating as it forms on a polymer. The team used PETRA III to observe the earliest stages in the growth of a metal-polymer hybrid material as a film of gold was applied to a polymer carrier, in a process that can be used in industrial applications. The group’s research, which it presented now in the journal Nanoscale Horizons, not only offers important new insights into how innovative hybrid nanomaterials form, it also sets a new world record in the temporal resolution achieved using GISAXS, a surface-sensitive scattering technique.

Metal-polymer materials form the basis of modern flexible electronics, such as organic field effect transistors (OFET) or novel television screens (OLED). A detailed understanding of the manufacturing process is essential in order to manufacture such composites using smaller amounts of starting materials, to make them more energy-efficient and to be able to use them more flexibly.

Read more on the DESY website

Image: Experimental setup on beamline P03: The high-brilliance X-ray beam from PETRA III (magenta) is scattered by the surface structures while gold atoms are rapidly deposited on wafer-thin layers of plastic. The deflected X-ray light is recorded using a special high-speed camera designed at DESY. The sophisticated analysis of the real-time data obtained provides clues about the change in the sizes, distances and density profile of the resulting metal-polymer boundary layer

Credit: DESY/M. Schwartzkopf