B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
|
Diamond Proposal Number(s):
[43895]
Open Access
Abstract: X-ray photoelectron spectroscopy (XPS) is a major technique in catalyst research due to its ability to determine chemical states on the surface. Near ambient pressure XPS (NAP-XPS) enables in situ analysis, offering valuable insight into catalytic processes. However, modern catalysts are often supported on non-conductive supports such as TiO2 or SiO2, which can present significant challenges for XPS analysis due to charging and differential charging. These issues can distort spectral data, rendering data unusable and wasting valuable instrument time. While several sample preparation strategies exist, many are limited by not allowing high temperature analysis, the risk of sample loss (e.g., from powder flaking off), or continued susceptibility to charging. In this work, we introduce a simple, robust, and time-efficient method for mounting catalyst powders by compressing them between aluminium foil disks. This approach provides excellent sample hold, minimises charging effects, and is suitable for high-temperature NAP-XPS analysis and synchrotron x-ray sources. The method addresses key limitations of conventional preparation techniques and enables more reliable characterisation of insulating catalyst materials.
|
Aug 2026
|
|
I06-Nanoscience (XPEEM)
|
Dafu
Zhao
,
Zisheng
Tang
,
Jinfeng
Liu
,
Zhiyi
Hu
,
Zhiwen
Yin
,
Jieheng
Lv
,
Xiaobin
Liao
,
Xiaoqian
Wang
,
Yingfei
Liu
,
Damin
Liu
,
Lihua
Chen
,
Bao-Lian
Su
,
Dongyuan
Zhao
,
Yong
Liu
Open Access
Abstract: Practical electrochemical energy conversion requires electrocatalysts that coordinate multiple elementary steps at spatially distinct active sites, yet atomic-level control of such site-specific reactivity within a single heterogeneous particle remains challenging. Here we propose and realize atomic-scale gradient strain as a design concept for heterogeneous electrocatalysis. Using Pd@Pt core-shell tetrahedra as a model system, we construct a continuous lattice-strain gradient across individual 3–4 atomic-layer Pt {111} epitaxial shells, where lattice-mismatch-driven compression relaxes from edges to center regions. This single-particle strain gradient, spanning approximately −8% to −2%, spatially links *O2 activation at highly compressed sites with *OH weakening at moderately compressed sites through kinetically accessible intermediate redistribution. The catalysts exhibit competitive oxygen reduction reaction performance, with mass and specific activities of 2.19 A mgPt⁻1 and 3.01 mA cm⁻2 at 0.9 V vs reversible hydrogen electrode, while retaining 91% activity after 20 k cycles. In membrane electrode assemblies, they achieve 0.57 A mgPt⁻1, and peak power densities of 2.10 W cm⁻2 in H2 − O2 and 1.16 W cm⁻2 in H2−air, with over 90% performance retention after 20 k cycles.
|
Jul 2026
|
|
E01-JEM ARM 200CF
|
Diamond Proposal Number(s):
[45820]
Abstract: Atomic-scale characterisation of thin buried layers in oxide heterostructures is often limited by the reduced sensitivity of conventional Z-contrast high-angle annular dark-field (HAADF) imaging to light elements and low-density regions. Here, a Sc2O3/Er2O3/Si heterostructure was investigated using aberration-corrected scanning transmission electron microscope (STEM) with simultaneous HAADF and integrated differential phase contrast (iDPC) imaging, with site-specific cross-sectional specimens prepared by scanning electron microscope-plasma focused ion beam (SEM-PFIB) using a Xe-ion beam under identical acquisition conditions to enable direct contrast comparison. Although HAADF clearly resolves the heavy rare-earth oxide layers and reveals a broad interfacial region with contrast variations indicative of structural complexity, simultaneous STEM-iDPC imaging resolves a distinct ∼3 nm buried interfacial layer with substantially greater clarity. Additional high-resolution transmission electron microscopy (HRTEM) and electron energy-loss spectroscopy (EELS) analyses reveal oxygen enrichment and local structural ordering within this region, indicating that it is chemically and structurally distinct from both crystalline Si and bulk Er2O3. The combined observations are consistent with an oxygen-rich Er–Si–O transition layer. These results demonstrate the capability of STEM-iDPC to reveal buried interfacial structure and highlight the value of combining HAADF, iDPC, HRTEM and spectroscopy for comprehensive characterisation of oxide heterostructures.
|
Jul 2026
|
|
I07-Surface & interface diffraction
|
Olivia
Gough
,
Katherine
Trinkaus
,
Pascal
Kaienburg
,
Zhenlong
Li
,
Andrea E.
Lauritzen
,
Jonathan
Rawle
,
Hugo
Norris
,
James
Hilfiker
,
Joel
Smith
,
Alessandro
Veneri
,
Gregory
Su
,
Moritz
Riede
Diamond Proposal Number(s):
[30773, 32922]
Abstract: The microstructure of organic small molecule (SM) layers in organic solar cells (OSCs) strongly influences device performance by impacting light absorption, charge transport, and recombination. We demonstrate that ellagic acid (EA), a naturally derived templating layer, induces substantial morphological and thus optoelectronic changes in the vacuum thermally evaporated (VTE) donor molecule DCV5T-Me(3,3). Using in situ grazing incidence wide-angle X-ray scattering (GIWAXS) during thin film deposition in the purpose-built MINERVA VTE chamber at Diamond Light Source, we show that a 5 nm EA layer reorients DCV5T-Me from an edge-on to a face-on molecular packing motif. This templating effect persists for up to around 90 nm of film thickness.
Through UV-vis spectrophotometry and photoluminescence (PL) spectroscopy, we observe a shift towards H-aggregation and decreased light absorption in the donor molecule with the EA template. Atomic force microscopy (AFM) shows that the donor morphology changes as a function of thickness from the donor-templating interface. In DCV5T-Me(3,3):C60 bulk heterojunction devices, the EA layer helps retain donor crystallinity and enhances short circuit current (J
), despite the lower absorption. Maximum power conversion efficiency in our devices is achieved with a 5 nm templating layer, which provides sufficient structural templating while maintaining partial interfacial contact for efficient charge extraction. We hypothesise that the improvement in J
is likely driven by enhanced charge carrier dynamics due to the orientation change, shift toward H-aggregation, and change in growth mode.
|
Jun 2026
|
|
B16-Test Beamline
|
Diamond Proposal Number(s):
[36299, 34545]
Open Access
Abstract: This study investigates the lattice strain induced by Ge:Sb alloy films on Ge substrates. Metastable films are formed by UV pulsed laser melting (PLM) of a Sb-coated Ge substrate. We fabricate thin Ge:Sb layers, systematically varying processing parameters and crystal orientation to study strain and strain-relaxation-induced defects. High-resolution X-Ray diffraction and electrical characterization revealed extremely high strain values as well as ultra-low resistivity induced by Sb. Maximum strain before the onset of strain relaxation was found to depend on crystal orientation with the Ge (1 1 1) orientation yielding the highest strain values. By combining structural as well as electrical information, we estimated Sb contribution to lattice expansion, separating electronically active from inactive fractions. Strain optimization was applied to an innovative application that is the production of bent crystals for high energy particle beam deflection and radiation production. Bending tests on thin Ge substrates confirmed the method, with controlled PLM processing allowing inducing quantifiable curvature with smallest achievable radii of 4.5 m. Exploiting non-equilibrium doping/alloying to exceed equilibrium Sb solubility is promising for applications ranging from ultra-low-resistivity layers in scaled nano-electronic devices to bent crystals for advanced systems like crystal-based undulators, enabling new approaches to high-energy photon production.
|
Jun 2026
|
|
I06-Nanoscience (XPEEM)
|
Benjamin A.
Brereton
,
Soumyarup
Hait
,
Ahmet
Yagmur
,
Christy
Kinane
,
Francesco
Maccherozzi
,
Michele
Conroy
,
Satoshi
Sasaki
,
Thomas A.
Moore
,
Sarnjeet S.
Dhesi
,
Sean
Langridge
,
Christopher H.
Marrows
Diamond Proposal Number(s):
[37770, 38770]
Open Access
Abstract: Topological insulators and skyrmion-hosting, chiral magnetic multilayers are two well-explored areas of modern condensed matter physics, each offering unique advantages for spintronics applications. In this paper, we demonstrate the optimization process for the growth of a Bi2Se3/buffer/[Pt/CoB/Ru]×𝑁 heterostructure that combines these two material classes: the Bi2Se3 epilayer was grown by molecular beam epitaxy before transfer under ultrahigh vacuum to a separate growth chamber where the polycrystalline metallic multilayer was sputter deposited. The structure of the samples was characterized by cofitted x-ray and polarized neutron reflectometry measurements and scanning transmission electron microscopy. Polarized neutron models and standard magnetometry show that a buffer layer exceeding a critical thickness is required to obtain the desired uniform, perpendicular magnetic anisotropy in every magnetic layer in the multilayer. Samples with both Ta and Mo buffers were used requiring thicknesses of 1.5 and 0.9 nm, respectively. In minimizing the Bi2Se3 terracing, buffered samples yield well-defined, out-of-plane, magnetic domains suitable for spin-orbit torque-induced manipulation as determined by x-ray photoemission electron microscopy.
|
Jun 2026
|
|
I07-Surface & interface diffraction
|
Jian
Mao
,
Qichun
Gu
,
Yunzhou
Deng
,
Milos
Dubajic
,
Thomas A.
Selby
,
Yorrick
Boeije
,
Xinjuan
Li
,
Yang
Lu
,
Zhengkang
Qu
,
Sebastiaan
Hoek
,
Linfeng
Pan
,
Weidong
Xu
,
Tianjun
Liu
,
Yuqi
Sun
,
Yu
Zhang
,
Benedetta
Gaggio
,
Zimu
Wei
,
Zher Ying
Ooi
,
Yutong
Han
,
Alessandro J.
Mirabelli
,
Eunyoung
Choi
,
Shenyu
Nie
,
Yi
Shen
,
Hayley
Gilbert
,
Yuanle
Tian
,
Xian Wei
Chua
,
Joo Sung
Kim
,
Xiaoliang
Mo
,
Fengxian
Xie
,
Jianlu
Wang
,
Judith L.
Macmanus-Driscoll
,
Meikang
Han
,
Junhao
Chu
,
Neil C.
Greenham
,
Henning
Sirringhaus
,
Caterina
Ducati
,
Tiarnan A. S.
Doherty
,
Paul A.
Midgley
,
Miguel
Anaya
,
Samuel D.
Stranks
Diamond Proposal Number(s):
[32266]
Open Access
Abstract: Achieving ultranarrow spectral linewidth and broad spectral tunability in light-emitting diodes (LEDs) remains challenging due to linewidth broadening from compositional and size heterogeneities. Here we report an interface-regulated vapour crystallization strategy that enables precise control over the spectral linewidth of solution-processed halide perovskite thin films. Underlying materials that exhibit minimal molecular interactions with perovskite precursors, exemplified by poly(9-vinylcarbazole), facilitate smooth ion diffusion and crystallization assisted by dimethylformamide vapour. This mechanism leads to perovskite films with both horizontal and vertical homogeneity and low inhomogeneous broadening comparable to that of perovskite single crystals. We demonstrate perovskite films with ultranarrow photoluminescence linewidths of 13.6 nm, 13.7 nm, 13.8 nm and 14.4 nm for emissions at 464 nm, 474 nm, 483 nm and 522 nm, respectively. This enables us to achieve sky-blue perovskite LEDs with narrow electroluminescence linewidths of 14.7 nm and a peak external quantum efficiency of 24.6%, with comparable linewidths and performance in LEDs spanning the pure blue to pure green. This work offers a practical and scalable strategy to realize narrow spectral linewidth, broad spectral tunability and high performance in thin film LEDs.
|
Jun 2026
|
|
B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
|
Ellen M.
Kiens
,
Nicolas
Gauquelin
,
Arno
Annys
,
Emma
Van Der Minne
,
Iris C. G.
Van Den Bosch
,
Matthijs A.
Van Spronsen
,
Zezhong
Zhang
,
Annick
De Backer
,
Sandra
Van Aert
,
Jo
Verbeeck
,
Gertjan
Koster
,
Bastian
Mei
,
Frank M. F.
De Groot
,
Christoph
Baeumer
Diamond Proposal Number(s):
[33107, 31118]
Abstract: Transition metal oxides exhibit a wide range of tunable electronic properties arising from the complex interplay of charge, spin, and lattice degrees of freedom, governed by their 𝑑 orbital configurations, making them particularly interesting for oxide electronics and (electro)catalysis. Perovskite oxide heterointerfaces offer a promising route to engineer these orbital states. In this work, we tune the Co3𝑑 orbital occupancy in LaCoO3 from a partial 𝑑7 to a partial 𝑑5 state through interfacial engineering with LaTiO3, LaMnO3, LaAlO3, and LaNiO3. Using x-ray absorption spectroscopy combined with charge transfer multiplet calculations, we identify differences in the Co valence and spin state for the series of oxide heterostructures. LaTiO3 and LaMnO3 interfaces result in interfacial charge transfer towards LaCoO3, resulting in a partial 𝑑7 orbital occupancy, while a LaNiO3 interface results in a partial Co 𝑑5 occupancy. Strikingly, a LaAlO3 spacer layer between LaNiO3 and LaCoO3 results in a Co 𝑑6 low-spin state. These results indicate that the Co spin state, like the valence state, is governed by the interfacial environment. High-resolution scanning transmission electron microscopy imaging reveals a clear connection between strain and spin configuration, emphasizing the importance of structural control at oxide interfaces. Overall, this work demonstrates that interfacial engineering simultaneously governs orbital occupancy and spin state in correlated oxides, advancing spin-engineering strategies in correlated oxides and offering new insights for the rational design of functional oxide heterostructures.
|
Jun 2026
|
|
I06-Nanoscience (XPEEM)
|
Diamond Proposal Number(s):
[6230, 1771]
Open Access
Abstract: Epitaxial films of the ferromagnetic manganite La0.7Sr0.3MnO3 on substrates of the ferroelectric perovskite BaTiO3 are known to display sharp magnetic changes and large magnetoelectric effects when the film is strained by the substrate undergoing thermally driven structural transitions and ferroelectric domain switching, respectively. However, only a single component of the in-plane magnetization has been hitherto imaged. Here we present magnetic vector maps—obtained from photoemission electron microscopy images with magnetic contrast from x-ray magnetic circular dichroism—to show that the electrically and thermally driven changes of local and global magnetization are deterministically influenced by the state of the substrate while also being complex and sample dependent. Our findings, supported by ferromagnetic resonance data and vibrating sample magnetometry, reveal that the behavior of La0.7Sr0.3MnO3 films on BaTiO3 substrates is not well predicted from knowledge of each system, probably due to long-range strain between BaTiO3 domains. In the future, it would be interesting to reduce complexity by patterning the film into regions between which magnetic communication is negligible.
|
May 2026
|
|
I10-Beamline for Advanced Dichroism - scattering
|
Duncan
Miertschin
,
Alessandro R.
Mazza
,
Balaram
Regmi
,
Sundar
Kunwar
,
Poshan
Kandel
,
Ryan
Mueller
,
Clayton
Hearn
,
Peter
Bencok
,
David A.
Jack
,
Thomas
Prokscha
,
Andreas
Suter
,
Zaher
Salman
,
Alan
Farhan
,
Thomas Zac
Ward
Diamond Proposal Number(s):
[38952]
Open Access
Abstract: Chemical disorder in compositionally complex perovskite oxides generates a broad distribution of exchange pathways and spin states, but the microscopic origin and spatial homogeneity of the resulting magnetic phases remain debated. Here, we tune the Mn fraction (x = 0.2–0.6) in epitaxial La(Cr, Mn, Fe, Co, Ni)O3 thin films and resolve the coupled evolution of valence, spin state, and magnetism using element-specific x-ray absorption spectroscopy and x-ray magnetic circular dichroism (XMCD). Mn enrichment drives an internal redistribution of charge, in which Mn evolves toward a Mn3+-rich mixed valence, while Co converts from predominantly Co3+ to high-spin Co2+. This valence/spin-state coupling amplifies the Mn- and Co-derived ferromagnetic response by nearly an order of magnitude while increasing the magnetic onset temperature to at least 250 K, whereas Fe and Cr remain essentially trivalent with weak dichroism. Depth-resolved low-energy muon spin spectroscopy (LE-μSR) shows magnetic homogeneity through the film thickness, with a secondary relaxation maximum near 25 K indicating a low-temperature dynamical crossover consistent with frustrated magnetism in a strongly disordered spin lattice.
|
May 2026
|
|
