Synthesis of our materials relies on the careful combination of two or more chemical reagents – e.g., the solutions of the metal and organic linker in MOFs – under highly controlled conditions. Temperature, solvent, pH and mixing are crucial to control the chemical reactions that underpin self-assembly and crystallisation in order to generate pure materials for further study.
Characterisation of as-synthesised materials is performed using standard analytical techniques of chemistry and materials science, which probe different aspects of their structure, such as crystallinity (powder X-ray diffraction), chemical functionality (infrared spectroscopy), particle morphology (electron microscopy), thermal stability (thermogravimetry), conductivity (impedance spectroscopy).
Detailed structural analysis is performed to understand our materials better, and the techniques we use depend on what’s of most interest. Single crystal X-ray diffraction can determine exactly where the atoms lie in a material that give rise to its properties; we use in-house diffractometers for routine work and synchrotron X-rays for more complex studies, including high pressure behaviour or challenging materials.
In situ techniques are really useful to study how materials form or behave under a variety of conditions, such as during synthesis or under high temperature, pressure or electric fields. We use them to give unparalleled insight into the fundamental structure-property relationships that govern the behaviour of functional materials.
Computational methods are increasingly being used to improve analysis of our experimental data. For example, sequential Rietveld refinement to powder diffraction data can determine how structures change as a function of time, composition or temperature. We collaborate with experts in computational chemistry, who simulate how atoms interact in our materials, helping to verify and understand our experimental observations.
Central facilities are used to obtain high-resolution experimental data that give cutting-edge insight into the structures of our materials. We also exploit the high flux and tuneable energies of synchrotron X-ray sources, such as Diamond, to perform in-situ experiments.
Yeung Research Group at UoB 