Diamond Light Source - Annual Review 2022/23 - Concise Edition

D I A M O N D L I G H T S O U R C E A N N U A L R E V I E W 2 0 2 2 / 2 3 D I A M O N D L I G H T S O U R C E A N N U A L R E V I E W 2 0 2 2 / 2 3 26 27 1 2 Imaging andMicroscopy Group T he Imaging and Microscopy Group brings together eight experimental facilities (I08, I08-1, DIAD, I12, I13-1, I13-2, I14 and the electron Physical Science Imagine Centre [ePSIC]), which use electrons and X-rays to image samples under different experimental conditions across a diverse range of length scales and time scales. The ability to extract image sample properties in minute detail lends itself to a wide range of scientific areas, from chemistry and catalysis to environmental science, materials science, biology, medicine, and cultural heritage. Studies from the group this year include the search of life on Mars, tomography to help study back pain, and perovskite material for new solar materials. Searching for life and for our origins are two sides of the same coin In 1996, researchers at NASA Johnson Space Center released a paper in Science entitled “Possible relic biogenic activity in Mars meteorite ALH84001”. This caused intense scientific examination of this meteorite, ultimately leading to the formation of the field of Astrobiology and renewed interest in sending missions to Mars. After several years, the scientific consensus was that there was no evidence of Martian life in the meteorite, but the question of organic material remained ambiguous. So the question remained for many years: if ALH84001 does not contain signs of martian life, what is the nature of organic material in this meteorite, and what is its origin? A team of researchers undertook a series of investigations to spatially resolve the presence, nature and possible synthesis mechanisms for the organic material in ALH84001. At Diamond’s I08 beamline, they carried out high spatial resolution STXM analysis across the C and N edges to look at the presence and bonding environment of the carbon present. From these analyses, the team were able to show that the organic carbon was synthesised in situ on Mars in two processes: serpentinisation and carbonation. These two organic synthesis mechanisms had not been seen on Mars before and are indicative of water-rock reactions 3.6 billion years ago. Water-rock interactions are relevant to planetary habitability, influencing mineralogical diversity and the production of organic molecules. Steele, A. et al. DOI: 10.1126/ science.abg7905 Detailedmeasurement of spinal disc mechanics provides insight into common back pain The leading cause of years lived with disability is from people suffering with lower back pain. It severely affects the quality of life of all global populations. The spine intervertebral discs (IVD) are the soft tissue in the spinal column. When injured or degenerated, they are responsible for the majority of these lower back pain cases. Currently, only symptomatic treatment or spinal surgery is available; therefore, understanding the mechanical pathogenesis of degeneration is crucial to developing non-invasive therapies. Researchers used synchrotron Computed Tomography (sCT) on Diamond’s I13-2 beamline to investigate collagen fibre bundles in 3D throughout an intact native rat lumbar IVD under increasing compressive load. By directly examining the functional response of intact spinal discs, in high enough detail to observe the critical collagen fibres, this study contributed to the understanding of disc degradation and failure. Portions of the disc that fail most frequently (posterior-lateral) have an inherently different fibre architecture from regions less prone to failure (anterior) and have a lower capacity to respond to compressive loading. The level of detail in these observations, with tens of thousands of individual fibres visualised and measured within each region, is essential to a full understanding of disc mechanics. The authors also provide a roadmap for attempts to restore spinal tissues to a more functional state. Being able to perform detailed characterisation of numerous individual collagen fibres from in situ imaging of intact tissues and structures will enhance our understanding of tissue biomechanics. Disney, CM. et al . DOI: 10.1016/j.actbio.2021.10.012 Nanoscale impurities seed degradation in novel solar materials Perovskite materials offer a cheaper alternative to silicon for producing solar cells and also show great potential for other optoelectronic applications, including energy-efficient LEDs and X-ray detectors. Metal halide salts - abundant andmuch cheaper to process than crystalline silicon - can be prepared in a liquid ink used to print a thin film of the material. In the past decade, improvements in the design and fabrication of metal halide perovskite (MHP) based solar cells have seen their efficiencies rise to compete with incumbent technologies and have laid the pathway to commercialisation. However, MHP stability, and thus the longevity of these light-harvesting devices, remains deficient. A multidisciplinary team of researchers used Diamond’s Hard X-ray Nanoprobe beamline (I14) and the electron Physical Science Imaging Centre (ePSIC) to gain new insight into the perovskite materials that hold so much potential in the field of optoelectronics. Their findings suggest that the localised presence of phase impurities are direct indicators of failure points in the absorber layer. The detection of such species through nanoscopic screening (e.g. high resolution electron microscopy) offers a means of predicting sites of instability during film optimisation and manufacturing for application in solar cells. New approaches should be developed to realise scalable, uniformly tilted and, thus, photo- stable MHP films on the manufacturing line. This research could significantly accelerate the development of long lasting, commercially available perovskite photovoltaics. Macpherson, S. et al . DOI: 10.1038/s41586- 022-04872-1