I07-Surface & interface diffraction
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Chieh-Szu
Huang
,
Danbi
Kim
,
Wenyan
Yang
,
Yang
Lu
,
Robert J. E.
Westbrook
,
Huagui
Lai
,
Zimu
Wei
,
Chaeyeon
Lee
,
Fan
Fu
,
Neil C.
Greenham
,
Bo Ram
Lee
,
Samuel D.
Stranks
Diamond Proposal Number(s):
[32266]
Open Access
Abstract: Amphiphilic polymer conetworks (APCNs), composed of nanoscale phase-separated hydrophilic and hydrophobic domains, have recently attracted interest for passive photonic applications like wearable luminescent solar concentrators. Here, their utility is extended by integrating APCNs into the active layer of organic photovoltaics (OPVs), enabling the incorporation of down-conversion luminophores that are otherwise incompatible with conventional OPV architectures. The APCN scaffold confines hydrophilic luminophores within hydroxyl acrylate domains, while the hydrophobic PM6:Y6 bulk heterojunction (BHJ) resides in the polydimethylsiloxane domains. Luminophores are chosen for selective phase affinity and complementary absorption to the BHJ. Devices incorporating dicyanomethylene-4H-pyran (DCM) luminophores show enhanced photocurrent, with short-circuit current increasing from 25.7 to 27.3 mA cm−2, while maintaining an open-circuit voltage of 0.86 V. Transient absorption spectroscopy reveals delayed ground-state bleach in PM6 and Y6, consistent with efficient exciton replenishment via energy transfer from luminophores. Grazing-incidence wide-angle X-ray scattering shows that luminophore molecular planarity and dihedral angles influence BHJ packing via van der Waals interactions, impacting charge transport. This work presents a multifunctional approach to enhance optoelectronic devices by embedding functional moieties within APCNs, offering insights from photonic, optoelectronic, and structural perspectives and establishing APCNs as a versatile platform for next-generation device engineering.
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Nov 2025
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Emma
Van Der Minne
,
Priscila
Vensaus
,
Vadim
Ratovskii
,
Seenivasan
Hariharan
,
Jan
Behrends
,
Cesare
Franchini
,
Jonas
Fransson
,
Sarnjeet S.
Dhesi
,
Felix
Gunkel
,
Florian
Gossing
,
Georgios
Katsoukis
,
Ulrike I.
Kramm
,
Magalí
Lingenfelder
,
Qianqian
Lan
,
Yury V.
Kolen'Ko
,
Yang
Li
,
Ramsundar Rani
Mohan
,
Jeffrey
Mccord
,
Lingmei
Ni
,
Eva
Pavarini
,
Rossitza
Pentcheva
,
David H.
Waldeck
,
Michael
Verhage
,
Anke
Yu
,
Zhichuan J.
Xu
,
Piero
Torelli
,
Silvia
Mauri
,
Narcis
Avarvari
,
Anja
Bieberle-Hütter
,
Christoph
Baeumer
Open Access
Abstract: A central challenge in water electrolysis lies with the oxygen evolution reaction (OER) where the formation of molecular oxygen (O2) is hindered by the constraint of angular momentum conservation. While the reactants OH− or H2O are diamagnetic (DM), the O2 product has a paramagnetic (PM) triplet ground state, requiring a change in spin configuration when being formed. This constraint has prompted interest in spin-selective catalysts as a means to facilitate OER. In this context, the roles of magnetism and chirality-induced spin selectivity (CISS) in promoting the OER reaction have recently been investigated through both theoretical and experimental studies. However, pinpointing the key principles and their relative contribution in mediating spin-enhancement remains a significant challenge. This roadmap offers a forward-looking perspective on current experimental trends and theoretical developments in spin-enhanced OER electrocatalysis and outlines strategic directions for integrating incisive experiments and operando approaches with computational modeling to disentangle key mechanisms. By providing a conceptual framework and identifying critical knowledge gaps, this perspective aims to guide researchers toward dedicated experimental and computational studies that will deepen the understanding of spin-induced OER enhancement and accelerate the development of next-generation catalysts.
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Oct 2025
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I13-2-Diamond Manchester Imaging
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Iain
Malone
,
Secil
Unsal
,
R. Scott
Young
,
Matthew P.
Jones
,
Francesco
Spanu
,
Shashidhara
Marathe
,
Rhodri
Jervis
,
Hugh G. C.
Hamilton
,
Christopher M.
Zalitis
,
Thomas S.
Miller
,
Alexander J. E.
Rettie
Diamond Proposal Number(s):
[35192]
Open Access
Abstract: Anion exchange membrane water electrolysers are held back by the low durability of the ionomer in the membrane and catalyst layers. Studying ionomer degradation in these systems is challenging because the main mechanisms - which result in catalyst detachment, membrane thinning, and loss of cationic functionality - have opposing effects on the cell potential. Electrochemical measurements alone are therefore insufficient for elucidating the underlying causes of degradation. To address this, a bespoke miniature-electrolyser-cell is developed for X-ray microtomography imaging of membrane electrode assemblies at 1.6 µm resolution. This setup enables the study of the entire active volume of the electrolyser under static and operando conditions and is validated against standard 5 cm2 laboratory cells. An operando investigation of degradation in Fumasep-based catalyst-coated membranes reveals both significant membrane thinning and loss of membrane ionic conductivity during stability testing, leading to increased ohmic resistance and cell potential. In contrast, a Selemion membrane shows minimal changes in thickness and conductivity and is significantly more stable compared to Fumasep when exposed to synchrotron radiation. This platform has relevance for operando studies of electrochemical materials and devices generally, including proton exchange membrane electrolysers, fuel cells, and CO2 electrolysers using both lab-based and synchrotron X-ray sources.
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Sep 2025
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B18-Core EXAFS
I09-Surface and Interface Structural Analysis
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Muhammad
Ans
,
Gaurav C.
Pandey
,
Innes
Mcclelland
,
Naresh
Gollapally
,
Harry
Gillions
,
Beth I. J.
Johnston
,
Matthew J. W.
Ogley
,
James A.
Gott
,
Eleni
Fiamegkou
,
Veronica
Celorrio
,
Pardeep K.
Thakur
,
Tien-Lin
Lee
,
Serena A.
Cussen
,
Ashok S.
Menon
,
Louis F. J.
Piper
Diamond Proposal Number(s):
[30104, 33553]
Open Access
Abstract: Single-crystalline LiNiO2 (SC-LNO), a high-energy-density Li-ion cathode material, suffers from poor long-term electrochemical performance when cycled above 4.2 V (vs Li+/Li). In this study, this degradation is evaluated using SC-LNO–graphite pouch cells electrochemically aged within a stressful voltage window (2.5–4.4 V) using a constant-current constant-voltage (CC-CV) protocol. Notable capacity fade is observed after one hundred cycles at C/3 rate, in addition to an increase in the overall electrochemical cell impedance. Operando X-ray diffraction data reveal that, despite no significant long-range bulk structural changes, (de-)lithiation of the aged SC-LNO becomes kinetically hindered after 100 cycles. Aging-induced changes in the short-range structure and charge compensation are evaluated through a multi-model quantitative analysis of the operando X-ray absorption spectroscopy data. While the electrochemical aging does not result in particle cracking, soft X-ray absorption spectroscopy data revealed the reconstruction of the cathode surface to a dense rock salt-like layer after long-term cycling, which acts as a kinetic trap for Li+ diffusion. Therefore, even under stressful conditions, it is the surface reconstruction that dominates the overall cathode degradation by reducing the Li+ mobility and leading to the capacity fade. Cathode surface engineering will therefore be key to improving the long-term electrochemical performance of SC-LNO cathodes.
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May 2025
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I07-Surface & interface diffraction
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Diamond Proposal Number(s):
[36553]
Open Access
Abstract: The efficiency of organic solar cells has raised drastically in the past years. However, there is an undeniable lack of hole transport layers that can provide high carrier selectivity, low defect density, and high processing robustness, simultaneously. In this work, this issue is addressed by studying defect generation and surface passivation of nickel oxide (NiOx). It is revealed that the generation of high oxidation state species on NiOx surface lowers contact resistance but hinders charge extraction when employed as transport layer in organic solar cells. By using them as coordination centers, a straightforward surface modification strategy is implemented using (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz) that enhances charge extraction and increases the solar cell efficiency from 11.46% to 17.12%. Additionally, the robustness of this modification across different deposition methods of the carbazole molecule is demonstrated. Finally, by fine-tuning the Fermi level using various carbazole-based molecules, and in particular with ((4-(7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid (4PADCB), a power conversion efficiency of 17.29% is achieved, with an outstanding combination of a VOC of 0.888 V and a fill factor of 80%.
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Jan 2025
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I07-Surface & interface diffraction
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Feray
Ünlü
,
Alejandra
Florez
,
Keely
Dodd-Clements
,
Lennart K.
Reb
,
Michael
Götte
,
Matthias
Grosch
,
Fengning
Yang
,
Senol
Öz
,
Florian
Mathies
,
Sanjay
Mathur
,
Daniel
Ramirez
,
Franklin
Jaramillo
,
Eva
Unger
Diamond Proposal Number(s):
[36427]
Open Access
Abstract: Halide perovskite solar cells are approaching commercialization, with solution processing emerging as a key method for large-scale production. This study introduces a significant advancement: using non-toxic solvents like water and alcohol in perovskite precursor inks facilitated by the protic ionic liquid methylammonium propionate (MAP). MAP effectively dissolves perovskite precursors such as lead acetate and methylammonium iodide, enabling the first stable water-based perovskite precursor ink suitable for one-step slot-die coating. This new ink formulation contrasts with conventional dimethylformamide (DMF) and dimethylsulfoxide (DMSO)-based inks, as evidenced by in-situ grazing incidence wide-angle X-ray scattering (GIWAXS), which revealed an intermediate-free liquid-to-solid transition. In-situ mass spectrometry also showed that organic molecules evaporate during annealing, resulting in a crystalline perovskite phase. Optimization of the solvent mixture to H2O/IPA/MAP enabled successful slot-die coating, yielding perovskite solar cells with an efficiency of up to 10%. This eco-friendly ink reduces toxicity and environmental impact compared to DMF-based inks, offering a longer shelf life and the possibility of using the ink in ambient conditions. This pioneering work represents the first report of a water-based green ink formulation for one-step thin film coating at room-temperature conditions by slot-die coating, highlighting its potential for sustainable commercial applications.
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Jan 2025
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I07-Surface & interface diffraction
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Matteo
Degani
,
Riccardo
Pallotta
,
Giovanni
Pica
,
Masoud
Karimipour
,
Alessandro
Mirabelli
,
Kyle
Frohna
,
Miguel
Anaya
,
Tianyu
Xu
,
Chang-Qi
Ma
,
Samuel D.
Stranks
,
Monica Lira
Cantù
,
Giulia
Grancini
Diamond Proposal Number(s):
[32266]
Open Access
Abstract: Interface engineering using self-assembled 2D perovskite interfaces is a consolidated route to efficient and durable perovskite solar cells. Whether the 2D perovskite forms a homogeneous conformal layer or is heterogeneously distributed on the surface, interface defects are passivated, leading to a general improvement in the device's open circuit voltage (VOC) and stability. Here, an innovative strategy is developed for manipulating the composition of the 2D/3D perovskite interface that results in the formation of a gradient halide distribution, which extends from the surface to the bulk. The use of a bromide-based 2D perovskite triggers a progressive Br/I exchange, affecting not only the surface but also the perovskite underneath. As a result, not only the device VOC improve, as expected, but also the photogenerated current is boosted, leading to a device efficiency of up to 24.4%. Such mixed halide gradient effectively passivates surface and bulk defects making the perovskite active layer more efficient and robust, as demonstrated by the superior device stability showing zero losses in performances upon 36 days (more than 800 h) test in outdoor conditions, those ones relevant for a marketable product.
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Dec 2024
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Biao
He
,
Pouya
Hosseini
,
Daniel
Escalera-López
,
Jonas
Schulwitz
,
Olaf
Rudiger
,
Ulrich
Hagemann
,
Markus
Heidelmann
,
Serena
Debeer
,
Martin
Muhler
,
Serhiy
Cherevko
,
Kristina
Tschulik
,
Tong
Li
Diamond Proposal Number(s):
[28433]
Open Access
Abstract: An atomic-scale understanding of how electrocatalyst surfaces reconstruct and transform during electrocatalytic reactions is essential for optimizing their activity and longevity. This is particularly important for the oxygen evolution reaction (OER), where dynamic and substantial structural and compositional changes occur during the reaction. Herein, a multimodal method is developed by combining X-ray fine structure absorption and photoemission spectroscopy, transmission electron microscopy, and atom probe tomography with electrochemical measurements to interrogate the temporal evolution of oxidation states, atom coordination, structure, and composition on Co2MnO4 and CoMn2O4 cubic spinel nanoparticle surfaces upon OER cycling in alkaline media. Co2MnO4 is activated at the onset of OER due to the formation of ≈2 nm Co-Mn oxyhydroxides with an optimal Co/Mn ratio of ≈3. As OER proceeds, Mn dissolution and redeposition occur for the CoMn oxyhydroxides, extending the OER stability of Co2MnO4. Such dynamic dissolution and redeposition are also observed for CoMn2O4, leading to the formation of less OER-active Mn-rich oxides on the nanoparticle surfaces. This study provides mechanistic insights into how dynamic surface reconstruction and transformation affect the activity and stability of mixed CoMn cubic spinels toward OER.
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Oct 2024
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B18-Core EXAFS
I21-Resonant Inelastic X-ray Scattering (RIXS)
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John-Joseph
Marie
,
Max
Jenkins
,
Jun
Chen
,
Gregory
Rees
,
Veronica
Celorrio
,
Jaewon
Choi
,
Stefano
Agrestini
,
Mirian
Garcia-Fernandez
,
Ke-Jin
Zhou
,
Robert A.
House
,
Peter G.
Bruce
Diamond Proposal Number(s):
[25785]
Open Access
Abstract: Achieving reversible O-redox through the formation of electron–holes on O could hold the key to a new generation of high energy density Na-ion cathodes. However, to date, it has only been demonstrated in a small handful of cathode materials and none of these materials exploit the dual benefit of high voltage transition metal redox and O-redox, instead relying on Mn3+/4+ capacity close to 2 V vs Na+/Na. Here, a new Na-ion cathode exhibiting electron–holes on O is demonstrated, P2-type Na0.67Li0.1Ni0.3Mn0.6O2, which also utilizes the high voltage Ni3+/4+ redox couple to deliver the highest reported energy density among this class of compound. By employing a low Li content and avoiding honeycomb ordering within the transition metal layer, it is possible to stabilize the hole states, and the high voltage plateau is preserved in Na0.67Li0.1Ni0.3Mn0.6O2 over cycling.
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Jul 2024
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I09-Surface and Interface Structural Analysis
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Christopher
Don
,
Thomas P.
Shalvey
,
Daniya A.
Sindi
,
Bradley
Lewis
,
Jack E. N.
Swallow
,
Leon
Bowen
,
Daniel F.
Fernandes
,
Tomas
Kubart
,
Deepnarayan
Biswas
,
Pardeep K.
Thakur
,
Tien-Lin
Lee
,
Jonathan D.
Major
Diamond Proposal Number(s):
[34642]
Open Access
Abstract: The evolution of Sb2Se3 heterojunction devices away from CdS electron transport layers (ETL) to wide bandgap metal oxide alternatives is a critical target in the development of this emerging photovoltaic material. Metal oxide ETL/Sb2Se3 device performance has historically been limited by relatively low fill factors, despite offering clear advantages with regards to photocurrent collection. In this study, TiO2 ETLs are fabricated via direct current reactive sputtering and tested in complete Sb2Se3 devices. A strong correlation between TiO2 ETL processing conditions and the Sb2Se3 solar cell device response under forward bias conditions is observed and optimized. Numerical device models support experimental evidence of a spike-like conduction band offset, which can be mediated, provided a sufficiently high conductivity and low interfacial defect density can be achieved in the TiO2 ETL. Ultimately, a SnO2:F/TiO2/Sb2Se3/P3HT/Au device with the reactively sputtered TiO2 ETL delivers an 8.12% power conversion efficiency (η), the highest TiO2/Sb2Se3 device reported to-date. This is achieved by a substantial reduction in series resistance, driven by improved crystallinity of the reactively sputtered anatase-TiO2 ETL, whilst maintaining almost maximum current collection for this device architecture.
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Jun 2024
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