I07-Surface & interface diffraction
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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.
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Jun 2026
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I07-Surface & interface diffraction
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Yuyun
Yao
,
Mustafeez Bashir
Shah
,
Wanpeng
Lu
,
Xian'E
Li
,
Rushil
Vasant
,
Zeinab
Hamid
,
Keren
Ai
,
Junfu
Tian
,
Maryam
Alsufyani
,
Jonathan
Rawle
,
Malina
Gaşpar
,
Qingpei
Wan
,
Rachael
Found
,
Wesley
Chen
,
Tomaž
Kotnik
,
Thuc-Quyen
Nguyen
,
Achilleas
Savva
,
James
Durrant
,
Iain
Mcculloch
Diamond Proposal Number(s):
[39430]
Open Access
Abstract: The development of organic electrochemical transistors (OECTs) critically depends on the design and characterization of mixed-conducting, high-performance conjugated polymers (CPs) as channel materials, particularly for n-type OECTs. In this study, we present a novel strategy to enhance the OECT performance of a semiconducting polymer film via a postdeposition ester pyrolysis of thermally cleavable side chains, thus facilitating ion incorporation and transport within the bulk. Our approach relies on the synthesis of a high glass-transition, rigid-rod polymer, able to withstand the pyrolysis temperature without deformation and maintain the voids formed from the pyrolysis reaction which removes the thermally cleavable ester side chains. After side-chain cleavage, the resulting film exhibits increased porosity, hydrophilicity, and crystallinity. By creating bulk porosity in thin films via this approach, ion diffusion is enhanced, resulting in a superior μC* figure of merit up to 158.85 F cm–1 V–1 s–1, and a corresponding increase in normalized transconductance (31.67 S cm–1). In addition, the device switching speed and long-term stability are also observed to increase, further demonstrating the benefit of nanoscale porosity for mixed conductivity semiconductors.
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Feb 2026
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I07-Surface & interface diffraction
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Alexandra L.
Martin
,
Philip N.
Jemmett
,
Thomas
Howitt
,
Mary H.
Wood
,
Liam R.
Cox
,
Timothy R.
Dafforn
,
Mario
Campana
,
Rebecca J. L.
Welbourn
,
Maximilian W. A.
Skoda
,
Luke A.
Clifton
,
Hadeel
Hussain
,
Jonathan L.
Rawle
,
Francesco
Carla
,
Christopher L.
Nicklin
,
Thomas
Arnold
,
Sarah L.
Horswell
Diamond Proposal Number(s):
[22078, 21088]
Open Access
Abstract: The reasons for the wide diversity of lipids found in natural cell membranes are still not fully understood but could potentially be exploited in treating disease and infection. This study aims to establish whether charge alone or specific chemical structure of an anionic lipid headgroup determines the structure and properties of model bacterial cell membranes. We compare different compositions of a zwitterionic lipid di-myristoyl phosphatidylethanolamine (DMPE) and two anionic lipids, di-myristoyl phosphatidylglycerol (DMPG) and tetra-myristoyl cardiolipin (TMCL). TMCL has a distinct condensing effect, increasing packing and decreasing the pressures of the phase transitions. Although relatively well solvated itself, TMCL does not substantially alter the solvation of mixed monolayers or bilayers. DMPE:TMCL mixtures have very similar electrochemical behaviour to mixtures of DMPE with di-myristoyl phosphatidylserine (DMPS) but DMPE:DMPG bilayers have greater surface charges. A ternary mixture representing an Escherichia coli membrane has similar electrochemical response to but is more tightly packed than DMPE:DMPG. These results establish the importance of the anionic lipid in modelling different types of cell membranes: DMPG will be required in model bacterial membranes and should not be replaced with DMPS. Even very small amounts of CL will have a measurable effect on structure, so its inclusion is important. Our results also highlight the importance of diverse techniques in understanding membrane behaviour: reflectivity measurements of monolayers over a range of surface pressure provide excellent insight into the electrochemical responses of lipid bilayers, while surface diffraction and infrared spectroscopy are much more sensitive to differences in packing between lipids.
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Aug 2025
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I04-Macromolecular Crystallography
I07-Surface & interface diffraction
I18-Microfocus Spectroscopy
I19-Small Molecule Single Crystal Diffraction
Optics
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Open Access
Abstract: A study on the thermal load of cryogenically cooled silicon in synchrotron double-crystal monochromators is presented, based on experimental data from four different beamlines at Diamond Light Source. Different amounts of power are deposited on the first monochromator crystal by varying the storage ring current. The resulting crystal deformation causes a decline in the diffraction efficiency when power and power density are above threshold values. The results are compatible with an analytical model of thermo-mechanical deformation. Acceptable monochromator heat load values are determined with this model, to ensure optimal function of the monochromator. This model, previously tested against finite element analyses, is now validated against measured data and it will be used as a tool for initial analysis of monochromator performance on upgraded photon sources.
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Jul 2025
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I07-Surface & interface diffraction
I09-Surface and Interface Structural Analysis
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Alessandro J.
Mirabelli
,
Birgit
Kammlander
,
Yang
Lu
,
Rahul Mahavir
Varma
,
Qichun
Gu
,
Karen
Radetzky
,
Thomas A.
Selby
,
Tianjun
Liu
,
Stefania
Riva
,
Zimu
Wei
,
Tien-Lin
Lee
,
Jonathan
Rawle
,
Hakan
Rensmo
,
Miguel
Anaya
,
Ute B.
Cappel
,
Samuel D.
Stranks
Diamond Proposal Number(s):
[30043, 32266, 30838, 33096]
Open Access
Abstract: To commercialize lead halide perovskites as light-emitting diodes (LEDs), the operational device lifetime needs to be drastically improved. For this to be achieved, an understanding of degradation behavior under bias is crucial. Herein, we perform operando measurements of the structural, chemical, and electronic changes using synchrotron-based grazing-incidence wide-angle X-ray scattering and hard X-ray photoelectron spectroscopy on full-stack deep blue mixed bromide/chloride lead halide perovskite LEDs. While a clear drop in optoelectronic performance is recorded under electrical bias, the accompanying X-ray scattering data reveals only minor changes in structural properties. However, photoelectron spectroscopy reveals substantial chemical changes at the electron-injecting interface after bias is applied, including the formation of unwanted metallic lead and a new chlorine species that is not in the perovskite structure. These operando approaches give important structural and interfacial perspectives to reveal the degradation mechanisms in these LEDs and highlight the need to address the top electron-injecting interface to realize step-changes in operational stability.
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Jun 2025
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I07-Surface & interface diffraction
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Gilles E.
Moehl
,
Samuel D.
Fitch
,
Katarina
Cicvarić
,
Yisong
Han
,
Ruomeng
Huang
,
Jonathan
Rawle
,
Li
Shao
,
Richard
Beanland
,
Philip N
Bartlett
,
Guy
Denuault
,
Andrew L.
Hector
Diamond Proposal Number(s):
[20593]
Open Access
Abstract: The process of electrochemically assisted surfactant assembly was followed in real time by grazing incidence small angle X-ray scattering with the aim to deconvolute the formation of mesoporous silica film and unwanted porous particles. The X-ray technique proved to be useful for the characterisation of this process, as it takes place at a very dynamic, solid/liquid interface. This paper shows the electrochemically driven onset and evolution of silica/surfactant structures. Additional control experiments indicate the formation of vertically aligned structures without the use of an electric field, although it seems to be beneficial increased pore ordering.
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Feb 2024
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I07-Surface & interface diffraction
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Daniel T. W.
Toolan
,
Michael P.
Weir
,
Shuangqing
Wang
,
Simon A.
Dowland
,
Zhilong
Zhang
,
James
Xiao
,
Jonathan
Rawle
,
Neil
Greenham
,
Richard
Friend
,
Akshay
Rao
,
Richard A. L.
Jones
,
Anthony J.
Ryan
Diamond Proposal Number(s):
[23587]
Open Access
Abstract: Hybrid small-molecule organic semiconductor / quantum dot blend films are attractive for high efficiency low-cost solar energy harvesting devices. Understanding and controlling the self-assembly of the organic semiconductor and quantum dots is crucial in optimising device performance, not only at a lab-scale but for large-scale high-throughput printing and coating methods. Here, in situ grazing incidence X-ray scattering (GIXS) is employed in order to gain direct insights into how small-molecule organic semiconductor / quantum dot blends self-assemble during blade coating. Results show that for two different archetypal organic small molecule:quantum dot blends, small-molecule crystallisation may either occur spontaneously or be mediated by the formation of quantum dot aggregates. Irrespective of the initial crystallisation route, the small-molecule crystallisation acts to exclude the quantum dot impurities from the growing crystalline matrix phase. These results provide important fundamental understanding of structure formation of small organic molecule:quantum dot films prepared via solution processing routes, compatible with large scale deposition manufacturing.
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May 2023
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I07-Surface & interface diffraction
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Alexandra L.
Martin
,
Philip N.
Jemmett
,
Thomas
Howitt
,
Mary H.
Wood
,
Andrew W.
Burley
,
Liam R.
Cox
,
Timothy R.
Dafforn
,
Rebecca J. L.
Welbourn
,
Mario
Campana
,
Maximilian W. A.
Skoda
,
Joseph J.
Thompson
,
Hadeel
Hussain
,
Jonathan L.
Rawle
,
Francesco
Carla
,
Christopher L.
Nicklin
,
Thomas
Arnold
,
Sarah L.
Horswell
Diamond Proposal Number(s):
[14670, 16423, 19542]
Open Access
Abstract: The effect of lipid composition on models of the inner leaflet of mammalian cell membranes has been investigated. Grazing incidence X-ray diffraction and X-ray and neutron reflectivity have been used to characterize lipid packing and solvation, while electrochemical and infrared spectroscopic methods have been employed to probe phase behavior in an applied electric field. Introducing a small quantity of the anionic lipid dimyristoylphosphatidylserine (DMPS) into bilayers of zwitterionic dimyristoylphosphatidylethanolamine (DMPE) results in a significant change in the bilayer response to an applied field: the tilt of the hydrocarbon chains increases before returning to the original tilt angle on detachment of the bilayer. Equimolar mixtures, with slightly closer chain packing, exhibit a similar but weaker response. The latter also tend to incorporate more solvent during this electrochemical phase transition, at levels similar to those of pure DMPS. Reflectivity measurements reveal greater solvation of lipid layers for DMPS > 30 mol %, matching the greater propensity for DMPS-rich bilayers to incorporate water. Taken together, the data indicate that the range of 10–35 mol % DMPS provides optimum bilayer properties (in flexibility and function as a barrier), which may explain why the DMPS content of cell membranes tends to be found within this range.
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Feb 2023
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I07-Surface & interface diffraction
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Philip N.
Jemmett
,
David C.
Milan
,
Richard J.
Nichols
,
Thomas
Howitt
,
Alexandra L.
Martin
,
Thomas
Arnold
,
Jonathan L.
Rawle
,
Christopher L.
Nicklin
,
Timothy R.
Dafforn
,
Liam R.
Cox
,
Sarah L.
Horswell
Diamond Proposal Number(s):
[15539, 18202]
Open Access
Abstract: Sphingolipids are an important class of lipids found in mammalian cell membranes with important structural and signaling roles. They differ from another major group of lipids, the glycerophospholipids, in the connection of their hydrocarbon chains to their headgroups. In this study, a combination of electrochemical and structural methods has been used to elucidate the effect of this difference on sphingolipid behavior in an applied electric field. N-Palmitoyl sphingomyelin forms bilayers of similar coverage and thickness to its close analogue di-palmitoyl phosphatidylcholine. Grazing incidence diffraction data show slightly closer packing and a smaller chain tilt angle from the surface normal. Electrochemical IR results at low charge density show that the difference in tilt angle is retained on deposition to form bilayers. The bilayers respond differently to increasing electric field strength: chain tilt angles increase for both molecules, but sphingomyelin chains remain tilted as field strength is further increased. This behavior is correlated with disruption of the hydrogen-bonding network of small groups of sphingomyelin molecules, which may have significance for the behavior of molecules in lipid rafts in the presence of strong fields induced by ion gradients or asymmetric distribution of charged lipids.
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Nov 2022
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I07-Surface & interface diffraction
I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[24359, 23666]
Open Access
Abstract: Membranes with high selectivity offer an attractive route to molecular separations, where technologies such as distillation and chromatography are energy intensive. However, it remains challenging to fine tune the structure and porosity in membranes, particularly to separate molecules of similar size. Here, we report a process for producing composite membranes that comprise crystalline porous organic cage films fabricated by interfacial synthesis on a polyacrylonitrile support. These membranes exhibit ultrafast solvent permeance and high rejection of organic dyes with molecular weights over 600 g mol−1. The crystalline cage film is dynamic, and its pore aperture can be switched in methanol to generate larger pores that provide increased methanol permeance and higher molecular weight cut-offs (1,400 g mol−1). By varying the water/methanol ratio, the film can be switched between two phases that have different selectivities, such that a single, ‘smart’ crystalline membrane can perform graded molecular sieving. We exemplify this by separating three organic dyes in a single-stage, single-membrane process.
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Jan 2022
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