E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[33068]
Abstract: In conclusion, this work demonstrates the powerful nature of SED, combined with 3D-ED, to explore sub-crystal nanostructures and defects in beam-sensitive soft materials.
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Jul 2024
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E02-JEM ARM 300CF
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Chao
Sun
,
Christopher M.
Pask
,
Sang T.
Pham
,
Emilio
Rapaccioli
,
Andrew J.
Britton
,
Stuart
Micklethwaite
,
Andrew
Bell
,
Maximilian O.
Besenhard
,
Rik
Drummond-Brydson
,
Ke-Jun
Wu
,
Sean M.
Collins
Diamond Proposal Number(s):
[33373]
Open Access
Abstract: The functional group-directed structures of coordination polymers (CPs) and metal–organic frameworks (MOFs) have made them key candidates for proton exchange membranes in fuel cell technologies. Sulfonate group chemistry is well established in proton conducting polymers but has seen less exploration in CPs. Here, we report solvent-directed crystal structures of Cu2+ and Ca2+ CPs constructed with naphthalenedisulfonate (NDS) and anthraquinone-1,5-disulfonate (ADS) ligands, and we correlate single crystal structures across this set with proton conductivities determined by electrochemical impedance spectroscopy. Starting from the Cu2+-based NDS and aminotriazolate MOF designated Cu-SAT and the aqueous synthesis of the known Ca2+-NDS structure incorporating water ligands, we now report a further five sulfonate CP structures. These syntheses include a direct synthesis of the primary degradation product of Cu-SAT in water, solvent-substituted Ca-NDS structures prepared using dimethylformamide and dimethylsulfoxide solvents, and ADS variants of Cu-SAT and Ca-NDS. We demonstrate a consistent 2D layer motif in the NDS CPs, while structural modifications introduced by the ADS ligand result in a 2D hydrogen bonding network with Cu2+ and aminotriazolate ligands and a 1D CP with Ca2+ in water. Proton conductivities across the set span 10−4 to >10−3 S cm−1 at 80 °C and 95% RH. These findings reveal an experimental structure–function relationship between proton conductivity and the tortuosity of the hydrogen bonding network and establish a general, cross-structure descriptor for tuning the sulfonate CP unit cell to systematically modulate proton conductivity.
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Jun 2024
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E02-JEM ARM 300CF
I07-Surface & interface diffraction
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Affan N.
Iqbal
,
Kieran W. P.
Orr
,
Satyawan
Nagane
,
Jordi Ferrer
Orri
,
Tiarnan A. S.
Doherty
,
Young-Kwang
Jung
,
Yu-Hsien
Chiang
,
Thomas A.
Selby
,
Yang
Lu
,
Alessandro J.
Mirabelli
,
Alan
Baldwin
,
Zher Ying
Ooi
,
Qichun
Gu
,
Miguel
Anaya
,
Samuel D.
Stranks
Diamond Proposal Number(s):
[32007]
Open Access
Abstract: Halide perovskites are excellent candidate materials for use in solar cell, LED, and detector devices, in part because their composition can be tuned to achieve ideal optoelectronic properties. Empirical efficiency optimisation has led the field towards compositions rich in FA (formamidinium) on the A-site and I on the X-site, with additional small amounts of MA (methylammonium) or Cs A-site cations and Br X-site anions. However, it is not clear how and why the specific compositions of alloyed, i.e., mixed component, halide perovskites relate to photo-stability of the materials. Here, we combine synchrotron grazing incidence wide-angle x-ray scattering, photoluminescence, high-resolution scanning electron diffraction measurements and theoretical modelling to reveal the links between material structure and photostability. Namely, we find that increased octahedral titling leads to improved photo-stability that is correlated with lower densities of performance-harming hexagonal polytype impurities. Our results uncover the structural signatures underpinning photo-stability and can therefore be used to make targeted changes to halide perovskites, bettering the commercial prospects of technologies based on these materials.
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May 2024
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E02-JEM ARM 300CF
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Jiajia
Suo
,
Bowen
Yang
,
Edoardo
Mosconi
,
Dmitry
Bogachuk
,
Tiarnan A. S.
Doherty
,
Kyle
Frohna
,
Dominik J.
Kubicki
,
Fan
Fu
,
Yeonju
Kim
,
Oussama
Er-Raji
,
Tiankai
Zhang
,
Lorenzo
Baldinelli
,
Lukas
Wagner
,
Ayodhya N.
Tiwari
,
Feng
Gao
,
Andreas
Hinsch
,
Samuel D.
Stranks
,
Filippo
De Angelis
,
Anders
Hagfeldt
Diamond Proposal Number(s):
[30750]
Open Access
Abstract: The stabilization of grain boundaries and surfaces of the perovskite layer is critical to extend the durability of perovskite solar cells. Here we introduced a sulfonium-based molecule, dimethylphenethylsulfonium iodide (DMPESI), for the post-deposition treatment of formamidinium lead iodide perovskite films. The treated films show improved stability upon light soaking and remains in the black α phase after two years ageing under ambient condition without encapsulation. The DMPESI-treated perovskite solar cells show less than 1% performance loss after more than 4,500 h at maximum power point tracking, yielding a theoretical T80 of over nine years under continuous 1-sun illumination. The solar cells also display less than 5% power conversion efficiency drops under various ageing conditions, including 100 thermal cycles between 25 °C and 85 °C and an 1,050-h damp heat test.
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Jan 2024
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E01-JEM ARM 200CF
I08-1-Soft X-ray Ptychography
I13-2-Diamond Manchester Imaging
I14-Hard X-ray Nanoprobe
I18-Microfocus Spectroscopy
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Cyril
Besnard
,
Ali
Marie
,
Sisini
Sasidharan
,
Petr
Buček
,
Jessica M.
Walker
,
Julia E.
Parker
,
Matthew C.
Spink
,
Robert A.
Harper
,
Shashidhara
Marathe
,
Kaz
Wanelik
,
Thomas E. J.
Moxham
,
Enrico
Salvati
,
Konstantin
Ignatyev
,
Michal M.
Klosowski
,
Richard M.
Shelton
,
Gabriel
Landini
,
Alexander M.
Korsunsky
Diamond Proposal Number(s):
[27749, 30684, 30691, 31005, 29256, 23873]
Open Access
Abstract: Caries, a major global disease associated with dental enamel demineralization, remains insufficiently understood to devise effective prevention or minimally invasive treatment. Understanding the ultrastructural changes in enamel is hampered by a lack of nanoscale characterization of the chemical spatial distributions within the dental tissue. This leads to the requirement to develop techniques based on various characterization methods. The purpose of the present study is to demonstrate the strength of analytic methods using a correlative technique on a single sample of human dental enamel as a specific case study to test the accuracy of techniques to compare regions in enamel. The science of the different techniques is integrated to genuinely study the enamel. The hierarchical structures within carious tissue were mapped using the combination of focused ion beam scanning electron microscopy with synchrotron X-ray tomography. The chemical changes were studied using scanning X-ray fluorescence (XRF) and X-ray wide-angle and small-angle scattering using a beam size below 80 nm for ångström and nanometer length scales. The analysis of XRF intensity gradients revealed subtle variations of Ca intensity in carious samples in comparison with those of normal mature enamel. In addition, the pathways for enamel rod demineralization were studied using X-ray ptychography. The results show the chemical and structural modification in carious enamel with differing locations. These results reinforce the need for multi-modal approaches to nanoscale analysis in complex hierarchically structured materials to interpret the changes of materials. The approach establishes a meticulous correlative characterization platform for the analysis of biomineralized tissues at the nanoscale, which adds confidence in the interpretation of the results and time-saving imaging techniques. The protocol demonstrated here using the dental tissue sample can be applied to other samples for statistical study and the investigation of nanoscale structural changes. The information gathered from the combination of methods could not be obtained with traditional individual techniques.
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Jul 2023
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[20198]
Open Access
Abstract: Intentionally disordered metal–organic frameworks (MOFs) display rich functional behaviour. However, the characterisation of their atomic structures remains incredibly challenging. X-ray pair distribution function techniques have been pivotal in determining their average local structure but are largely insensitive to spatial variations in the structure. Fe-BTC (BTC = 1,3,5-benzenetricarboxylate) is a nanocomposite MOF, known for its catalytic properties, comprising crystalline nanoparticles and an amorphous matrix. Here, we use scanning electron diffraction to first map the crystalline and amorphous components to evaluate domain size and then to carry out electron pair distribution function analysis to probe the spatially separated atomic structure of the amorphous matrix. Further Bragg scattering analysis reveals systematic orientational disorder within Fe-BTC’s nanocrystallites, showing over 10° of continuous lattice rotation across single particles. Finally, we identify candidate unit cells for the crystalline component. These independent structural analyses quantify disorder in Fe-BTC at the critical length scale for engineering composite MOF materials.
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May 2023
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B16-Test Beamline
DIAD-Dual Imaging and Diffraction Beamline
E01-JEM ARM 200CF
E02-JEM ARM 300CF
I08-Scanning X-ray Microscopy beamline (SXM)
I12-JEEP: Joint Engineering, Environmental and Processing
I13-1-Coherence
I13-2-Diamond Manchester Imaging
I14-Hard X-ray Nanoprobe
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Open Access
Abstract: Hard dental tissues possess a complex hierarchical structure that is particularly evident in enamel, the most mineralised substance in the human body. Its complex and interlinked organisation at the Ångstrom (crystal lattice), nano-, micro-, and macro-scales is the result of evolutionary optimisation for mechanical and functional performance: hardness and stiffness, fracture toughness, thermal, and chemical resistance. Understanding the physical–chemical–structural relationships at each scale requires the application of appropriately sensitive and resolving probes. Synchrotron X-ray techniques offer the possibility to progress significantly beyond the capabilities of conventional laboratory instruments, i.e., X-ray diffractometers, and electron and atomic force microscopes. The last few decades have witnessed the accumulation of results obtained from X-ray scattering (diffraction), spectroscopy (including polarisation analysis), and imaging (including ptychography and tomography). The current article presents a multi-disciplinary review of nearly 40 years of discoveries and advancements, primarily pertaining to the study of enamel and its demineralisation (caries), but also linked to the investigations of other mineralised tissues such as dentine, bone, etc. The modelling approaches informed by these observations are also overviewed. The strategic aim of the present review was to identify and evaluate prospective avenues for analysing dental tissues and developing treatments and prophylaxis for improved dental health.
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Apr 2023
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
E02-JEM ARM 300CF
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Longxiang
Liu
,
Liqun
Kang
,
Arunabhiram
Chutia
,
Jianrui
Feng
,
Martyna
Michalska
,
Pilar
Ferrer
,
David
Grinter
,
Georg
Held
,
Yeshu
Tan
,
Fangjia
Zhao
,
Fei
Guo
,
David
Hopkinson
,
Christopher
Allen
,
Yanbei
Hou
,
Junwen
Gu
,
Ioannis
Papakonstantinou
,
Paul
Shearing
,
Dan
Brett
,
Ivan P.
Parkin
,
Guanjie
He
Diamond Proposal Number(s):
[29340, 32501, 30614, 29809, 32058]
Open Access
Abstract: The electrochemical synthesis of hydrogen peroxide (H2O2) via a two-electron (2e-) oxygen reduction reaction (ORR) process provides a promising alternative to replace the energy-intensive anthraquinone process. However, the development of efficient electrocatalysts is still facing lots of challenges like insufficient understanding of active sites. Herein, we develop a facile template-protected strategy to synthesize a highly active quinone-rich porous carbon catalyst (PCC) for H2O2 electrochemical production. The optimized PCC900 exhibits unprecedented activity and selectivity, of which the onset potential reaches 0.83 V vs. reversible hydrogen electrode in 0.1 M KOH and the H2O2 selectivity is over 95 % in a wide potential range. Comprehensive synchrotron-based near-edge X-ray absorption fine structure (NEXAFS) spectroscopy combined with electrocatalytic characterizations reveals the positive correlation between quinone content and 2e- ORR performance. The effectiveness of chair-form quinone groups as the most efficient active sites is highlighted by the molecule-mimic strategy and theoretical analysis.
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Mar 2023
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E02-JEM ARM 300CF
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Haobo
Dong
,
Ruirui
Liu
,
Xueying
Hu
,
Fangjia
Zhao
,
Liqun
Kang
,
Longxiang
Liu
,
Jianwei
Li
,
Yeshu
Tan
,
Yongquan
Zhou
,
Dan J. L.
Brett
,
Guanjie
He
,
Ivan
Parkin
Diamond Proposal Number(s):
[30614, 29809]
Open Access
Abstract: A stable cathode–electrolyte interface (CEI) is crucial for aqueous zinc-ion batteries (AZIBs), but it is less investigated. Commercial binder poly(vinylidene fluoride) (PVDF) is widely used without scrutinizing its suitability and cathode-electrolyte interface (CEI) in AZIBs. A water-soluble binder is developed that facilitated the in situ formation of a CEI protecting layer tuning the interfacial morphology. By combining a polysaccharide sodium alginate (SA) with a hydrophobic polytetrafluoroethylene (PTFE), the surface morphology, and charge storage kinetics can be confined from diffusion-dominated to capacitance-controlled processes. The underpinning mechanism investigates experimentally in both kinetic and thermodynamic perspectives demonstrate that the COO− from SA acts as an anionic polyelectrolyte facilitating the adsorption of Zn2+; meanwhile fluoride atoms on PTFE backbone provide hydrophobicity to break desolvation penalty. The hybrid binder is beneficial in providing a higher areal flux of Zn2+ at the CEI, where the Zn-Birnessite MnO2 battery with the hybrid binder exhibits an average specific capacity 45.6% higher than that with conventional PVDF binders; moreover, a reduced interface activation energy attained fosters a superior rate capability and a capacity retention of 99.1% in 1000 cycles. The hybrid binder also reduces the cost compared to the PVDF/NMP, which is a universal strategy to modify interface morphology.
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Dec 2022
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[30614, 29809, 32058]
Open Access
Abstract: Platinum (Pt) is regarded as a promising electrocatalyst for hydrogen evolution reaction (HER). However, its application in an alkaline medium is limited by the activation energy of water dissociation, diffusion of H+, and desorption of H*. Moreover, the formation of effective structures with a low Pt usage amount is still a challenge. Herein, guided by the simulation discovery that the edge effect can boost local electric field (LEF) of the electrocatalysts for faster proton diffusion, platinum nanocrystals on the edge of transition metal phosphide nanosheets are fabricated. The unique heterostructure with ultralow Pt amount delivered an outstanding HER performance in an alkaline medium with a small overpotential of 44.5 mV and excellent stability for 80 h at the current density of −10 mA cm−2. The mass activity of as-prepared electrocatalyst is 2.77 A mg−1Pt, which is 15 times higher than that of commercial Pt/C electrocatalysts (0.18 A mg−1Pt). The density function theory calculation revealed the efficient water dissociation, fast adsorption, and desorption of protons with hybrid structure. The study provides an innovative strategy to design unique nanostructures for boosting HER performances via achieving both synergistic effects from hybrid components and enhanced LEF from the structural edge effect.
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Nov 2022
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