I22-Small angle scattering & Diffraction
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Johanna
Heimonen
,
Cecilia
Bruschi
,
Asaminew Y.
Shimolo
,
Marle E. J.
Vleugels
,
Lukas
Marcos Celada
,
Sozan
Darabi
,
Viktor
Gueskine
,
Daniel
Primetzhofer
,
Christian
Müller
,
Bence
Fehér
,
Peter
Olsén
,
Renee
Kroon
Diamond Proposal Number(s):
[39422]
Open Access
Abstract: The transition to sustainable electronics requires electroactive materials that are processable in green solvents, operationally stable, and recyclable or recoverable at their end of life. This work explores recoverable electroactive cellulose coatings using a carboxylate-functionalized polar polythiophene (PCAT-K). PCAT-K is water-processable and can be reversibly fixated onto cellulose threads by modulation of the secondary interactions via acid–base chemistry, showing promise for circular material use. To obtain electrically conducting PCAT-K-cellulose threads, acid-mediated oxygen doping of the PCAT-K with p-toluenesulfonic acid was explored but led to undesired covalent cross-linking and loss of solubility and recoverability. Through spectroscopic and electrochemical analyses, it is shown that the covalent cross-linking originates from hydrogen peroxide generation during the doping process, which further reacts with PCAT to form hydroxyl radicals. To suppress radical formation, potassium iodide is introduced as a benign additive that catalytically decomposes hydrogen peroxide, preventing covalent cross-linking while maintaining electrical conductivity and recoverability. While the additive can negatively affect cellulose substrates at long doping times, this strategy allows for stable, conductive, and removable electroactive coatings on cellulose threads using water as the sole solvent. This study highlights a more reliable synthetic route to the water-processable conjugated polymer PCAT-K and suggests a mechanistic origin of acid-mediated oxygen doping-induced covalent cross-linking with a practical strategy to overcome it.
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Jul 2026
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[30280]
Open Access
Abstract: Two new multiresonant thermally activated delayed fluorescence (MR-TADF) emitters, BINAP-BN1 and BINAP-BN2, containing a 1,1'-binaphthalene (BINAP) unit and a varying number of tCzBN units (one in BINAP-BN1 and two in BINAP-BN2), were synthesized. In toluene, both showed emission maxima at ca. 490 nm, photoluminescence quantum yields (ΦPL) up to 82%, and ΔEST of ∼0.15 eV. Significant differences in their optoelectronic properties emerged as their 1 wt.% doped films in mCBP. BINAP-BN1 has a ΦPL of 82%, while that of BINAP-BN2 is 64%. Aggregation-induced emission broadening at higher doping concentrations is suppressed for BINAP-BN1 but not for BINAP-BN2, attributed to the less sterically hindered BINAP moiety in the former. These photophysical differences translated in device performance. The organic light-emitting diodes (OLEDs) with BINAP-BN1 and BINAP-BN2 achieved maximum external quantum efficiencies (EQEmax) of 20.1 and 14.1%, respectively, at corresponding CIE coordinates of (0.08, 0.42) and (0.10, 0.50). A hyperfluorescence (HF) device employing HDT-1 as sensitizer and BINAP-BN1 as terminal emitter improved EQEmax to 22.0% and reduced efficiency roll-off to 32% at 1000 cd/m2, compared to 52% in the binary device. In comparison, a device with 1 wt.% tCzBN in mCBP showed an EQEmax of 15.6%, rising to 21.6% in a HF configuration.
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Jun 2026
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I06-Nanoscience (XPEEM)
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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.
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Jun 2026
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I07-Surface & interface diffraction
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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.
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Jun 2026
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B16-Test Beamline
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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.
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Jun 2026
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E02-JEM ARM 300CF
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Christopher J. H.
Smalley
,
Colan E.
Hughes
,
Tom
Willhammar
,
Raj
Pandya
,
Semion K.
Saikin
,
Duncan N.
Johnstone
,
Jeffrey
Gorman
,
Jooyoung
Sung
,
Gianni
Jacucci
,
Paul A.
Midgley
,
Demie M.
Kepaptsoglou
,
Quentin M.
Ramasse
,
Akshay
Rao
,
Kenneth D. M.
Harris
,
Sean M.
Collins
Diamond Proposal Number(s):
[20527]
Open Access
Abstract: Organic semiconductors continue to make substantial performance gains from photovoltaics to electronics. However, understanding how differences in solid-state structure give rise to large differences in energy transport properties remains unresolved. We report that microcrystals of two perylene diimide (PDI) derivatives differing only in their terminal groups [cyclohexyl (CH) and 4-heptyl (ST)] have exciton diffusion coefficients differing by more than two orders of magnitude. Applying state-of-the-art techniques for microcrystal structure determination, we report the crystal structures of CH-PDI and two polymorphs of ST-PDI. Scanning electron diffraction reveals a range of crystallographic defects in ST-PDI microcrystals, attributed to polymorph intergrowths, while electron energy loss spectroscopy links these defects to nanoscale electronic structure changes. Computational modeling demonstrates that rotational disorder explains the difference in exciton diffusion coefficients. Our observations establish the importance of defect-induced orientational disorder as a source of extrinsic energetic disorder, highlighting the need for defect management in organic semiconductor technologies.
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May 2026
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I10-Beamline for Advanced Dichroism - scattering
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Diamond Proposal Number(s):
[36751]
Abstract: The collective precession of magnetization manifests itself as magnon modes. These modes are governed by complex-valued vectorial eigenfunctions, which have remained experimentally challenging to observe. Here we introduce X-ray magnetic vector chronoscopy (XMVC), a time-resolved resonant scattering method that reconstructs the full magnetization dynamics with angular resolution of 0.1° (±0.01°). Applied to a synthetic antiferromagnetic multilayer (Si/NiFe (8 nm)/Ru (0.8 nm)/CoFeB (5.5 nm)), XMVC enables magnon state tomography, by directly measuring the nanoscale vectorial eigenfunctions of hybridized modes arising from magnon–magnon coupling. This approach provides full access to the system’s non-Hermitian Hamiltonian, revealing the complex-valued coupling strengths and non-orthogonal eigenbases. These results establish XMVC as an experimental platform for studying nanoscale spin systems by extracting the eigenfunctions of the system.
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May 2026
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[31878, 33382, 34606, 34607]
Open Access
Abstract: Nanoscale phase separation in polymer semiconductor blends significantly influences their mechanical, optical, and transport properties, and uncontrolled phase separation ultimately contributes to the long-term degradation of devices. Recent advances in electron microscopy have enabled imaging and diffraction-based analysis of polymer components, but these approaches are typically limited to blends with components exhibiting sharp differences in crystallinity or molecular structure. Here, we employ low-dose scanning electron diffraction to characterize phase-separated domains of components with nearly identical molecular structure, namely poly(9,9-di-n-octylfluorenyl-2,7-diyl) (F8) and poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT). For semicrystalline blends, we demonstrate phase identification and crystallographic texture analysis. In fully amorphous systems with partial phase separation, we highlight the limitations of electron pair distribution function (ePDF) analysis. Instead, we exploit differences in angle-dependent scattering, coupled with calculated intramolecular scattering intensities, to reliably map distinct amorphous phases. Finally, we showcase this suite of techniques for characterizing a model device cross-section, prepared by cryogenic focused ion beam milling. These workflows decouple phase separation and crystallization processes in F8:F8BT blends, provide corroborating insights into F8 crystalline and amorphous intermolecular π − π stacking, and support the direct visualization of non-crystalline organic multilayer interfaces in cross-section needed for failure analysis in organic optoelectronics.
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May 2026
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I10-Beamline for Advanced Dichroism - scattering
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Roxana
Capu
,
Ryan
Thompson
,
C. Willem
Rischau
,
Marli R.
Cantarino
,
Premysl
Marsik
,
Sergey L.
Bud'Ko
,
Neven
Biškup
,
María
Varela
,
Yurii G.
Pashkevich
,
Serhii M.
Orel
,
Thomas
Prokscha
,
Andreas
Suter
,
Jiangtao
Zhao
,
Ugwumsinachi
Oji
,
Marco
Bonura
,
Peter
Bencok
,
Zaher
Salman
,
Stefano
Gariglio
,
Christian
Bernhard
,
Subhrangsu
Sarkar
Diamond Proposal Number(s):
[38112]
Open Access
Abstract: We report the dielectric and magnetic properties of epitaxial thin films of the high entropy oxide (HEO) perovskite Nd(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3, which orders magnetically below Tmag≈190 K. At T ≫ Tmag, the dielectric response reveals a Debye-type frequency dependence with a zero-frequency dielectric constant of
≈230–250. The dc bias voltage loops of
are reversible but exhibit three distinct peaks centred at zero and finite positive and negative voltage. We provide evidence that the zero-bias peak is governed by the oxygen sublattice while the finite bias peaks originate from cationic dipoles. The maximal response of the latter appears to be shifted to finite bias by a static uncompensated electric field due to a vertical gradient of the oxygen content. Below Tmag, this anomalous dielectric response is strongly suppressed, presumably by magnetostriction that counteracts and freezes the ionic displacements. These findings indicate a unique correlation between configurational entropy, dielectric response, and magnetic properties. In combination with a large dielectric strength, it enables a non-hysteretic tuning of the dielectric response of magnetoelectronic devices with multiple parameters like temperature, electric, and magnetic field. This HEO is equally interesting for fundamental studies of competing electric and magnetic orders in strongly disordered materials.
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Apr 2026
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I05-ARPES
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Chakradhar
Sahoo
,
Suman Kumar
Chakraborty
,
Anbalagan
Kousika
,
Alfred J. H.
Jones
,
Manas
Sharma
,
Thomas S.
Nielsen
,
Zhihao
Jiang
,
Ihsan A.
Kolasseri
,
Subhadip
Das
,
Matthew D.
Watson
,
Cephise
Cacho
,
Kenji
Watanabe
,
Takashi
Taniguchi
,
Yong P.
Chen
,
Tony F.
Heinz
,
Ananth
Govind Rajan
,
Prasana K.
Sahoo
,
Søren
Ulstrup
Diamond Proposal Number(s):
[36290, 38414]
Abstract: Atomic-scale control over band alignment in single-layer lateral heterostructures (LHSs) of dissimilar transition metal dichalcogenides (TMDCs) is critical for next-generation electronic, optoelectronic, and quantum technologies. However, direct experimental access to interfacial electronic states with nanometer precision remains a significant challenge. Here, we employ angle-resolved photoemission spectroscopy with nanoscale spatial resolution (nanoARPES) to directly map the epitaxial alignment and valence band evolution across the MoSe2–WSe2 LHSs. By combining nanoARPES with spatially resolved photoluminescence, we correlate the evolution of the valence band maximum and exciton features across both atomically sharp and compositionally graded diffusive interfaces. We identified type-II band alignments governed by both material composition and interstitial-induced modifications of band offsets in close agreement with density functional theory calculations. These results reveal fundamental mechanisms of electronic structure modulation at 1D TMDC heterointerfaces and provide a robust platform for tailored band engineering in van der Waals materials.
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Apr 2026
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