Our students have been involved in new and exciting interdisciplinary research and have published in leading high impact journals including Nature Chemistry, Nature Communications, JACS, Angewandte Chemie, Applied Physics Letters, ACS Nano, Nano Letters, Advanced Materials, Nature Protocols, PloS one, and many others.
A full list of the work published by our NanoDTC Students, Associates and others, acknowledging the NanoDTC grants EP/G037221, EP/L015978 and EP/S022953/1 is below. If you want to view the papers on google scholar, see here.
Some papers published by our students are also featured below with some additional contextual information.
Last updated: Mar 2021
Looking inside lithium-ion batteries
Spectroscopy and Electrocatalysis for a Sustainable Future
From waste to fuel: quantifying sustainability
Novel spin states discovered in silicon-based artificial atoms
A step forward in efficient artificial photosynthesis
Self-assembling hydrogels on microfluidic droplets that respond to light or chemical stimuli by disassembling
2023
Traberg, Walther C.; Uribe, Johana; Druet, Victor; Hama, Adel; Moysidou, Chrysanthi-Maria; Huerta, Miriam; McCoy, Reece; Hayward, Daniel; Savva, Achilleas; Genovese, Amaury M. R.; Pavagada, Suraj; Lu, Zixuan; Koklu, Anil; Pappa, Anna-Maria; Fitzgerald, Rebecca; Inal, Sahika; Daniel, Susan; Owens, Roisin M.
Organic Electronic Platform for Real-Time Phenotypic Screening of Extracellular-Vesicle-Driven Breast Cancer Metastasis Journal Article
In: ADVANCED HEALTHCARE MATERIALS, vol. 12, no. 27, 2023, ISSN: 2192-2640.
@article{WOS:000991610800001,
title = {Organic Electronic Platform for Real-Time Phenotypic Screening of
Extracellular-Vesicle-Driven Breast Cancer Metastasis},
author = {Walther C. Traberg and Johana Uribe and Victor Druet and Adel Hama and Chrysanthi-Maria Moysidou and Miriam Huerta and Reece McCoy and Daniel Hayward and Achilleas Savva and Amaury M. R. Genovese and Suraj Pavagada and Zixuan Lu and Anil Koklu and Anna-Maria Pappa and Rebecca Fitzgerald and Sahika Inal and Susan Daniel and Roisin M. Owens},
doi = {10.1002/adhm.202301194},
issn = {2192-2640},
year = {2023},
date = {2023-10-01},
journal = {ADVANCED HEALTHCARE MATERIALS},
volume = {12},
number = {27},
publisher = {WILEY},
address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA},
abstract = {Tumor-derived extracellular vesicles (TEVs) induce the
epithelial-to-mesenchymal transition (EMT) in nonmalignant cells to
promote invasion and cancer metastasis, representing a novel therapeutic
target in a field severely lacking in efficacious antimetastasis
treatments. However, scalable technologies that allow continuous,
multiparametric monitoring for identifying metastasis inhibitors are
absent. Here, the development of a functional phenotypic screening
platform based on organic electrochemical transistors (OECTs) for
real-time, noninvasive monitoring of TEV-induced EMT and screening of
antimetastatic drugs is reported. TEVs derived from the triple-negative
breast cancer cell line MDA-MB-231 induce EMT in nonmalignant breast
epithelial cells (MCF10A) over a nine-day period, recapitulating a model
of invasive ductal carcinoma metastasis. Immunoblot analysis and
immunofluorescence imaging confirm the EMT status of TEV-treated cells,
while dual optical and electrical readouts of cell phenotype are
obtained using OECTs. Further, heparin, a competitive inhibitor of cell
surface receptors, is identified as an effective blocker of TEV-induced
EMT. Together, these results demonstrate the utility of the platform for
TEV-targeted drug discovery, allowing for facile modeling of the
transient drug response using electrical measurements, and provide proof
of concept that inhibitors of TEV function have potential as
antimetastatic drug candidates.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
epithelial-to-mesenchymal transition (EMT) in nonmalignant cells to
promote invasion and cancer metastasis, representing a novel therapeutic
target in a field severely lacking in efficacious antimetastasis
treatments. However, scalable technologies that allow continuous,
multiparametric monitoring for identifying metastasis inhibitors are
absent. Here, the development of a functional phenotypic screening
platform based on organic electrochemical transistors (OECTs) for
real-time, noninvasive monitoring of TEV-induced EMT and screening of
antimetastatic drugs is reported. TEVs derived from the triple-negative
breast cancer cell line MDA-MB-231 induce EMT in nonmalignant breast
epithelial cells (MCF10A) over a nine-day period, recapitulating a model
of invasive ductal carcinoma metastasis. Immunoblot analysis and
immunofluorescence imaging confirm the EMT status of TEV-treated cells,
while dual optical and electrical readouts of cell phenotype are
obtained using OECTs. Further, heparin, a competitive inhibitor of cell
surface receptors, is identified as an effective blocker of TEV-induced
EMT. Together, these results demonstrate the utility of the platform for
TEV-targeted drug discovery, allowing for facile modeling of the
transient drug response using electrical measurements, and provide proof
of concept that inhibitors of TEV function have potential as
antimetastatic drug candidates.
Lewis, George R.; Ringe, Emilie; Midgley, Paul A.
Cones and spirals: Multi-axis acquisition for scalar and vector electron tomography Journal Article
In: ULTRAMICROSCOPY, vol. 252, 2023, ISSN: 0304-3991.
@article{WOS:001018967700001,
title = {Cones and spirals: Multi-axis acquisition for scalar and vector electron
tomography},
author = {George R. Lewis and Emilie Ringe and Paul A. Midgley},
doi = {10.1016/j.ultramic.2023.113775},
issn = {0304-3991},
year = {2023},
date = {2023-10-01},
journal = {ULTRAMICROSCOPY},
volume = {252},
publisher = {ELSEVIER},
address = {RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS},
abstract = {Electron tomography (ET) has become an important tool for understanding
the 3D nature of nanomaterials, with recent developments enabling not
only scalar reconstructions of electron density, but also vector
reconstructions of magnetic fields. However, whilst new signals have
been incorporated into the ET toolkit, the acquisition schemes have
largely kept to conventional single-axis tilt series for scalar ET, and
dual-axis schemes for magnetic vector ET. In this work, we explore the
potential of using multi-axis tilt schemes including conical and spiral
tilt schemes to improve reconstruction fidelity in scalar and magnetic
vector ET. Through a combination of sys-tematic simulations and a
proof-of-concept experiment, we show that spiral and conical tilt
schemes have the potential to produce substantially improved
reconstructions, laying the foundations of a new approach to electron
tomography acquisition and reconstruction.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
the 3D nature of nanomaterials, with recent developments enabling not
only scalar reconstructions of electron density, but also vector
reconstructions of magnetic fields. However, whilst new signals have
been incorporated into the ET toolkit, the acquisition schemes have
largely kept to conventional single-axis tilt series for scalar ET, and
dual-axis schemes for magnetic vector ET. In this work, we explore the
potential of using multi-axis tilt schemes including conical and spiral
tilt schemes to improve reconstruction fidelity in scalar and magnetic
vector ET. Through a combination of sys-tematic simulations and a
proof-of-concept experiment, we show that spiral and conical tilt
schemes have the potential to produce substantially improved
reconstructions, laying the foundations of a new approach to electron
tomography acquisition and reconstruction.
Pandya, Raj; Valzania, Lorenzo; Dorchies, Florian; Xia, Fei; Hugh, Jeffrey Mc; Mathieson, Angus; Tan, Hwee Jien; Parton, Thomas G.; Godeffroy, Louis; Mazloomian, Katrina; Miller, Thomas S.; Kanoufi, Frederic; Volder, Michael De; Tarascon, Jean-Marie; Gigan, Sylvain; Aguiar, Hilton B.; Grimaud, Alexis
Three-dimensional operando optical imaging of particle and electrolyte heterogeneities inside Li-ion batteries Journal Article
In: NATURE NANOTECHNOLOGY, vol. 18, no. 10, pp. 1185+, 2023, ISSN: 1748-3387.
@article{WOS:001054226500001,
title = {Three-dimensional operando optical imaging of particle and electrolyte
heterogeneities inside Li-ion batteries},
author = {Raj Pandya and Lorenzo Valzania and Florian Dorchies and Fei Xia and Jeffrey Mc Hugh and Angus Mathieson and Hwee Jien Tan and Thomas G. Parton and Louis Godeffroy and Katrina Mazloomian and Thomas S. Miller and Frederic Kanoufi and Michael De Volder and Jean-Marie Tarascon and Sylvain Gigan and Hilton B. Aguiar and Alexis Grimaud},
doi = {10.1038/s41565-023-01466-4},
issn = {1748-3387},
year = {2023},
date = {2023-10-01},
journal = {NATURE NANOTECHNOLOGY},
volume = {18},
number = {10},
pages = {1185+},
publisher = {NATURE PORTFOLIO},
address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},
abstract = {Confocal optical microscopy is used to visualize-at high speed-solid
(particle volume changes and phase-front velocities) and liquid
electrolyte (concentration polarization gradients) dynamics inside
operating batteries.
Understanding (de)lithiation heterogeneities in battery materials is key
to ensure optimal electrochemical performance. However, this remains
challenging due to the three-dimensional morphology of electrode
particles, the involvement of both solid- and liquid-phase reactants and
a range of relevant timescales (seconds to hours). Here we overcome this
problem and demonstrate the use of confocal microscopy for the
simultaneous three-dimensional operando measurement of lithium-ion
dynamics in individual agglomerate particles, and the electrolyte in
batteries. We examine two technologically important cathode materials:
LixCoO2 and LixNi0.8Mn0.1Co0.1O2. The surface-to-core transport velocity
of Li-phase fronts and volume changes are captured as a function of
cycling rate. Additionally, we visualize heterogeneities in the bulk and
at agglomerate surfaces during cycling, and image microscopic liquid
electrolyte concentration gradients. We discover that surface-limited
reactions and intra-agglomerate competing rates control (de)lithiation
and structural heterogeneities in agglomerate-based electrodes.
Importantly, the conditions under which optical imaging can be performed
inside the complex environments of battery electrodes are outlined.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
(particle volume changes and phase-front velocities) and liquid
electrolyte (concentration polarization gradients) dynamics inside
operating batteries.
Understanding (de)lithiation heterogeneities in battery materials is key
to ensure optimal electrochemical performance. However, this remains
challenging due to the three-dimensional morphology of electrode
particles, the involvement of both solid- and liquid-phase reactants and
a range of relevant timescales (seconds to hours). Here we overcome this
problem and demonstrate the use of confocal microscopy for the
simultaneous three-dimensional operando measurement of lithium-ion
dynamics in individual agglomerate particles, and the electrolyte in
batteries. We examine two technologically important cathode materials:
LixCoO2 and LixNi0.8Mn0.1Co0.1O2. The surface-to-core transport velocity
of Li-phase fronts and volume changes are captured as a function of
cycling rate. Additionally, we visualize heterogeneities in the bulk and
at agglomerate surfaces during cycling, and image microscopic liquid
electrolyte concentration gradients. We discover that surface-limited
reactions and intra-agglomerate competing rates control (de)lithiation
and structural heterogeneities in agglomerate-based electrodes.
Importantly, the conditions under which optical imaging can be performed
inside the complex environments of battery electrodes are outlined.
Bedingfield, Kalun; Elliott, Eoin; Gisdakis, Arsenios; Kongsuwan, Nuttawut; Baumberg, Jeremy J.; Demetriadou, Angela
Multi-faceted plasmonic nanocavities Journal Article
In: NANOPHOTONICS, vol. 12, no. 20, pp. 3931-3944, 2023, ISSN: 2192-8606.
@article{WOS:001079756800001,
title = {Multi-faceted plasmonic nanocavities},
author = {Kalun Bedingfield and Eoin Elliott and Arsenios Gisdakis and Nuttawut Kongsuwan and Jeremy J. Baumberg and Angela Demetriadou},
doi = {10.1515/nanoph-2023-0392},
issn = {2192-8606},
year = {2023},
date = {2023-10-01},
journal = {NANOPHOTONICS},
volume = {12},
number = {20},
pages = {3931-3944},
publisher = {WALTER DE GRUYTER GMBH},
address = {GENTHINER STRASSE 13, D-10785 BERLIN, GERMANY},
abstract = {Plasmonic nanocavities form very robust sub-nanometer gaps between
nanometallic structures and confine light within deep subwavelength
volumes to enable unprecedented control of light-matter interactions.
However, spherical nanoparticles acquire various polyhedral shapes
during their synthesis, which has a significant impact in controlling
many light-matter interactions, such as photocatalytic reactions. Here,
we focus on nanoparticle-on-mirror nanocavities built from three
polyhedral nanoparticles (cuboctahedron, rhombicuboctahedron,
decahedron) that commonly occur during the synthesis. Their photonic
modes have a very intricate and rich optical behaviour, both in the
near- and far-field. Through a recombination technique, we obtain the
total far-field produced by a molecule placed within these nanocavities,
to reveal how energy couples in and out of the system. This work paves
the way towards understanding and controlling light-matter interactions,
such as photocatalytic reactions and non-linear vibrational pumping, in
such extreme environments.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
nanometallic structures and confine light within deep subwavelength
volumes to enable unprecedented control of light-matter interactions.
However, spherical nanoparticles acquire various polyhedral shapes
during their synthesis, which has a significant impact in controlling
many light-matter interactions, such as photocatalytic reactions. Here,
we focus on nanoparticle-on-mirror nanocavities built from three
polyhedral nanoparticles (cuboctahedron, rhombicuboctahedron,
decahedron) that commonly occur during the synthesis. Their photonic
modes have a very intricate and rich optical behaviour, both in the
near- and far-field. Through a recombination technique, we obtain the
total far-field produced by a molecule placed within these nanocavities,
to reveal how energy couples in and out of the system. This work paves
the way towards understanding and controlling light-matter interactions,
such as photocatalytic reactions and non-linear vibrational pumping, in
such extreme environments.
Pujari, Arvind; Kim, Byung-Man; Sayed, Farheen N.; Sanders, Kate; Dose, Wesley M.; Mathieson, Angus; Grey, Clare P.; Greenham, Neil C.; Volder, Michael De
Does Heat Play a Role in the Observed Behavior of Aqueous Photobatteries? Journal Article
In: ACS ENERGY LETTERS, vol. 8, no. 11, pp. 4625-4633, 2023, ISSN: 2380-8195.
@article{WOS:001103652100001,
title = {Does Heat Play a Role in the Observed Behavior of Aqueous
Photobatteries?},
author = {Arvind Pujari and Byung-Man Kim and Farheen N. Sayed and Kate Sanders and Wesley M. Dose and Angus Mathieson and Clare P. Grey and Neil C. Greenham and Michael De Volder},
doi = {10.1021/acsenergylett.3c01627},
issn = {2380-8195},
year = {2023},
date = {2023-10-01},
journal = {ACS ENERGY LETTERS},
volume = {8},
number = {11},
pages = {4625-4633},
publisher = {AMER CHEMICAL SOC},
address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
abstract = {Light-rechargeable photobatteries have emerged as an elegant solution to
address the intermittency of solar irradiation by harvesting and storing
solar energy directly through a battery electrode. Recently, a number of
compact two-electrode photobatteries have been proposed, showing
increases in capacity and open-circuit voltage upon illumination. Here,
we analyze the thermal contributions to this increase in capacity under
galvanostatic and photocharging conditions in two promising photoactive
cathode materials, V2O5 and LiMn2O4. We propose an improved cell and
experimental design and perform temperature-controlled
photoelectrochemical measurements using these materials as
photocathodes. We show that the photoenhanced capacities of these
materials under 1 sun irradiation can be attributed mostly to thermal
effects. Using operando reflection spectroscopy, we show that the
spectral behavior of the photocathode changes as a function of the state
of charge, resulting in changing optical absorption properties. Through
this technique, we show that the band gap of V2O5 vanishes after
continued zinc ion intercalation, making it unsuitable as a photocathode
beyond a certain discharge voltage. These results and experimental
techniques will enable the rational selection and testing of materials
for next-generation photo-rechargeable systems.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
address the intermittency of solar irradiation by harvesting and storing
solar energy directly through a battery electrode. Recently, a number of
compact two-electrode photobatteries have been proposed, showing
increases in capacity and open-circuit voltage upon illumination. Here,
we analyze the thermal contributions to this increase in capacity under
galvanostatic and photocharging conditions in two promising photoactive
cathode materials, V2O5 and LiMn2O4. We propose an improved cell and
experimental design and perform temperature-controlled
photoelectrochemical measurements using these materials as
photocathodes. We show that the photoenhanced capacities of these
materials under 1 sun irradiation can be attributed mostly to thermal
effects. Using operando reflection spectroscopy, we show that the
spectral behavior of the photocathode changes as a function of the state
of charge, resulting in changing optical absorption properties. Through
this technique, we show that the band gap of V2O5 vanishes after
continued zinc ion intercalation, making it unsuitable as a photocathode
beyond a certain discharge voltage. These results and experimental
techniques will enable the rational selection and testing of materials
for next-generation photo-rechargeable systems.
Orr, Kieran W. P.; Diao, Jiecheng; Lintangpradipto, Muhammad Naufal; Batey, Darren J.; Iqbal, Affan N.; Kahmann, Simon; Frohna, Kyle; Dubajic, Milos; Zelewski, Szymon J.; Dearle, Alice E.; Selby, Thomas A.; Li, Peng; Doherty, Tiarnan A. S.; Hofmann, Stephan; Bakr, Osman M.; Robinson, Ian K.; Stranks, Samuel D.
Imaging Light-Induced Migration of Dislocations in Halide Perovskites with 3d Nanoscale Strain Mapping Journal Article
In: ADVANCED MATERIALS, 2023, ISSN: 0935-9648.
@article{WOS:001119392100001,
title = {Imaging Light-Induced Migration of Dislocations in Halide Perovskites
with 3d Nanoscale Strain Mapping},
author = {Kieran W. P. Orr and Jiecheng Diao and Muhammad Naufal Lintangpradipto and Darren J. Batey and Affan N. Iqbal and Simon Kahmann and Kyle Frohna and Milos Dubajic and Szymon J. Zelewski and Alice E. Dearle and Thomas A. Selby and Peng Li and Tiarnan A. S. Doherty and Stephan Hofmann and Osman M. Bakr and Ian K. Robinson and Samuel D. Stranks},
doi = {10.1002/adma.202305549},
issn = {0935-9648},
year = {2023},
date = {2023-10-01},
journal = {ADVANCED MATERIALS},
publisher = {WILEY-V C H VERLAG GMBH},
address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY},
abstract = {In recent years, halide perovskite materials have been used to make
high-performance solar cells and light-emitting devices. However,
material defects still limit device performance and stability. Here,
synchrotron-based Bragg coherent diffraction imaging is used to
visualize nanoscale strain fields, such as those local to defects, in
halide perovskite microcrystals. Significant strain heterogeneity within MAPbBr3 (MA = CH3NH3+) crystals is found in spite of their high
optoelectronic quality, and both < 100 & rang; and < 110 & rang; edge
dislocations are identified through analysis of their local strain
fields. By imaging these defects and strain fields in situ under
continuous illumination, dramatic light-induced dislocation migration
across hundreds of nanometers is uncovered. Further, by selectively
studying crystals that are damaged by the X-ray beam, large dislocation
densities and increased nanoscale strains are correlated with material
degradation and substantially altered optoelectronic properties assessed
using photoluminescence microscopy measurements. These results
demonstrate the dynamic nature of extended defects and strain in halide
perovskites, which will have important consequences for device
performance and operational stability.
Halide perovskites are exciting materials for optoelectronic devices.
Here, synchrotron-based Bragg coherent diffraction imaging is used to
visualize nanoscale strain fields and dislocation defects. By imaging
these defects and strain fields in situ under continuous illumination,
dramatic light-induced dislocation migration across hundreds of
nanometers is uncovered, and the impact of these defects on material
performance is unveiled.image},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
high-performance solar cells and light-emitting devices. However,
material defects still limit device performance and stability. Here,
synchrotron-based Bragg coherent diffraction imaging is used to
visualize nanoscale strain fields, such as those local to defects, in
halide perovskite microcrystals. Significant strain heterogeneity within MAPbBr3 (MA = CH3NH3+) crystals is found in spite of their high
optoelectronic quality, and both < 100 & rang; and < 110 & rang; edge
dislocations are identified through analysis of their local strain
fields. By imaging these defects and strain fields in situ under
continuous illumination, dramatic light-induced dislocation migration
across hundreds of nanometers is uncovered. Further, by selectively
studying crystals that are damaged by the X-ray beam, large dislocation
densities and increased nanoscale strains are correlated with material
degradation and substantially altered optoelectronic properties assessed
using photoluminescence microscopy measurements. These results
demonstrate the dynamic nature of extended defects and strain in halide
perovskites, which will have important consequences for device
performance and operational stability.
Halide perovskites are exciting materials for optoelectronic devices.
Here, synchrotron-based Bragg coherent diffraction imaging is used to
visualize nanoscale strain fields and dislocation defects. By imaging
these defects and strain fields in situ under continuous illumination,
dramatic light-induced dislocation migration across hundreds of
nanometers is uncovered, and the impact of these defects on material
performance is unveiled.image
Peri, Lorenzo; Prete, Domenic; Demontis, Valeria; Degoli, Elena; Ruini, Alice; Magri, Rita; Rossella, Francesco
Measuring thermal conductivity of nanostructures with the 3ω method: the need for finite element modeling Journal Article
In: NANOTECHNOLOGY, vol. 34, no. 43, 2023, ISSN: 0957-4484.
@article{WOS:001044522800001,
title = {Measuring thermal conductivity of nanostructures with the 3\textit{ω}
method: the need for finite element modeling},
author = {Lorenzo Peri and Domenic Prete and Valeria Demontis and Elena Degoli and Alice Ruini and Rita Magri and Francesco Rossella},
doi = {10.1088/1361-6528/acdc2c},
issn = {0957-4484},
year = {2023},
date = {2023-10-01},
journal = {NANOTECHNOLOGY},
volume = {34},
number = {43},
publisher = {IOP Publishing Ltd},
address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND},
abstract = {Conventional techniques of measuring thermal transport properties may be
unreliable or unwieldy when applied to nanostructures. However, a
simple, all-electrical technique is available for all samples featuring
high-aspect-ratio: the 3? method. Nonetheless, its usual formulation
relies on simple analytical results which may break down in real
experimental conditions. In this work we clarify these limits and
quantify them via adimensional numbers and present a more accurate,
numerical solution to the 3? problem based on the Finite Element Method
(FEM). Finally, we present a comparison of the two methods on
experimental datasets from InAsSb nanostructures with different thermal
transport properties, to stress the crucial need of a FEM counterpart to
3? measurements in nanostructures with low thermal conductivity.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
unreliable or unwieldy when applied to nanostructures. However, a
simple, all-electrical technique is available for all samples featuring
high-aspect-ratio: the 3? method. Nonetheless, its usual formulation
relies on simple analytical results which may break down in real
experimental conditions. In this work we clarify these limits and
quantify them via adimensional numbers and present a more accurate,
numerical solution to the 3? problem based on the Finite Element Method
(FEM). Finally, we present a comparison of the two methods on
experimental datasets from InAsSb nanostructures with different thermal
transport properties, to stress the crucial need of a FEM counterpart to
3? measurements in nanostructures with low thermal conductivity.
Sandoval, Miguel A. Cascales; Hierro-Rodriguez, A.; Ruiz-Gomez, S.; Skoric, L.; Donnelly, C.; Nino, M. A.; Vedmedenko, E. Y.; McGrouther, D.; McVitie, S.; Flewett, S.; Jaouen, N.; Foerster, M.; Fernandez-Pacheco, A.
Observation and formation mechanism of 360° domain wall rings in synthetic anti-ferromagnets with interlayer chiral interactions Journal Article
In: APPLIED PHYSICS LETTERS, vol. 123, no. 17, 2023, ISSN: 0003-6951.
@article{WOS:001133362200001,
title = {Observation and formation mechanism of 360° domain wall rings in
synthetic anti-ferromagnets with interlayer chiral interactions},
author = {Miguel A. Cascales Sandoval and A. Hierro-Rodriguez and S. Ruiz-Gomez and L. Skoric and C. Donnelly and M. A. Nino and E. Y. Vedmedenko and D. McGrouther and S. McVitie and S. Flewett and N. Jaouen and M. Foerster and A. Fernandez-Pacheco},
doi = {10.1063/5.0158119},
issn = {0003-6951},
year = {2023},
date = {2023-10-01},
journal = {APPLIED PHYSICS LETTERS},
volume = {123},
number = {17},
publisher = {AIP Publishing},
address = {1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA},
abstract = {The interlayer Dzyaloshinskii-Moriya interaction (IL-DMI) chirally
couples spins in different ferromagnetic layers of multilayer
heterostructures. So far, samples with IL-DMI have been investigated
utilizing magnetometry and magnetotransport techniques, where the
interaction manifests as a tunable chiral exchange bias field. Here, we
investigate the nanoscale configuration of the magnetization vector in a
synthetic anti-ferromagnet (SAF) with IL-DMI, after applying
demagnetizing field sequences. We add different global magnetic field
offsets to the demagnetizing sequence in order to investigate the states
that form when the IL-DMI exchange bias field is fully or partially
compensated. For magnetic imaging and vector reconstruction of the
remanent magnetic states, we utilize x-ray magnetic circular dichroism
photoemission electron microscopy, evidencing the formation of 360
degrees domain wall rings of typically 0.5-3.0 mu m in diameter. These
spin textures are only observed when the exchange bias field due to the
IL-DMI is not perfectly compensated by the magnetic field offset. From a
combination of micromagnetic simulations, magnetic charge distribution,
and topology arguments, we conclude that a non-zero remanent effective
field with components both parallel and perpendicular to the anisotropy
axis of the SAF is necessary to observe the rings. This work shows how
the exchange bias field due to IL-DMI can lead to complex metastable
spin states during reversal, important for the development of future
spintronic devices. (C) 2023 Author(s). All article content, except
where otherwise noted, is licensed under a Creative Commons Attribution
(CC BY) license (http:// creativecommons.org/licenses/by/4.0/).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
couples spins in different ferromagnetic layers of multilayer
heterostructures. So far, samples with IL-DMI have been investigated
utilizing magnetometry and magnetotransport techniques, where the
interaction manifests as a tunable chiral exchange bias field. Here, we
investigate the nanoscale configuration of the magnetization vector in a
synthetic anti-ferromagnet (SAF) with IL-DMI, after applying
demagnetizing field sequences. We add different global magnetic field
offsets to the demagnetizing sequence in order to investigate the states
that form when the IL-DMI exchange bias field is fully or partially
compensated. For magnetic imaging and vector reconstruction of the
remanent magnetic states, we utilize x-ray magnetic circular dichroism
photoemission electron microscopy, evidencing the formation of 360
degrees domain wall rings of typically 0.5-3.0 mu m in diameter. These
spin textures are only observed when the exchange bias field due to the
IL-DMI is not perfectly compensated by the magnetic field offset. From a
combination of micromagnetic simulations, magnetic charge distribution,
and topology arguments, we conclude that a non-zero remanent effective
field with components both parallel and perpendicular to the anisotropy
axis of the SAF is necessary to observe the rings. This work shows how
the exchange bias field due to IL-DMI can lead to complex metastable
spin states during reversal, important for the development of future
spintronic devices. (C) 2023 Author(s). All article content, except
where otherwise noted, is licensed under a Creative Commons Attribution
(CC BY) license (http:// creativecommons.org/licenses/by/4.0/).
Loeto, K.; Kusch, G.; Ghosh, S.; Kappers, M. J.; Oliver, R. A.
Quantitative analysis of carbon impurity concentrations in GaN epilayers by cathodoluminescence Journal Article
In: MICRON, vol. 172, 2023, ISSN: 0968-4328.
@article{WOS:001038605900001,
title = {Quantitative analysis of carbon impurity concentrations in GaN epilayers
by cathodoluminescence},
author = {K. Loeto and G. Kusch and S. Ghosh and M. J. Kappers and R. A. Oliver},
doi = {10.1016/j.micron.2023.103489},
issn = {0968-4328},
year = {2023},
date = {2023-09-01},
journal = {MICRON},
volume = {172},
publisher = {PERGAMON-ELSEVIER SCIENCE LTD},
address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND},
abstract = {In this work, a technique for quantifying carbon doping concentrations
in GaN:C/AlGaN buffer structures using cathodoluminescence (CL) is
presented. The method stems from the knowledge that the blue and yellow
lumi-nescence intensity in CL spectra of GaN varies with the carbon
doping concentration. By calculating the blue and yellow luminescence
peak intensities normalised to the peak GaN near-band-edge intensity for
GaN layers of known carbon concentrations, calibration curves that show
the change in normalised blue and yellow lumi-nescence intensity with
carbon concentration in the 1016 -1019 cm-3 range were derived at both
room tem-perature and 10 K. The utility of such calibration curves was
then examined by testing against an unknown sample containing multiple
carbon-doped GaN layers. The results obtained from CL using the
normalised blue luminescence calibration curves are in close agreement
with those from secondary-ion mass spectroscopy (SIMS). However,the
method fails when applying calibration curves obtained from the
normalised yellow luminescence likely due to the influence of native VGa
defects acting in this luminescence region. Although this work shows
that indeed CL can be used as a quantitative tool to measure carbon
doping concentrations in GaN:C, it is noted that the intrinsic
broadening effects innate to CL can make it difficult to differentiate
between the intensity variations in thin ( < 500 nm) multilayered GaN:C
structures such as the ones studied in this work.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
in GaN:C/AlGaN buffer structures using cathodoluminescence (CL) is
presented. The method stems from the knowledge that the blue and yellow
lumi-nescence intensity in CL spectra of GaN varies with the carbon
doping concentration. By calculating the blue and yellow luminescence
peak intensities normalised to the peak GaN near-band-edge intensity for
GaN layers of known carbon concentrations, calibration curves that show
the change in normalised blue and yellow lumi-nescence intensity with
carbon concentration in the 1016 -1019 cm-3 range were derived at both
room tem-perature and 10 K. The utility of such calibration curves was
then examined by testing against an unknown sample containing multiple
carbon-doped GaN layers. The results obtained from CL using the
normalised blue luminescence calibration curves are in close agreement
with those from secondary-ion mass spectroscopy (SIMS). However,the
method fails when applying calibration curves obtained from the
normalised yellow luminescence likely due to the influence of native VGa
defects acting in this luminescence region. Although this work shows
that indeed CL can be used as a quantitative tool to measure carbon
doping concentrations in GaN:C, it is noted that the intrinsic
broadening effects innate to CL can make it difficult to differentiate
between the intensity variations in thin ( < 500 nm) multilayered GaN:C
structures such as the ones studied in this work.
Simatos, Dimitrios; Jacobs, Ian E.; Dobryden, Illia; Nguyen, Malgorzata; Savva, Achilleas; Venkateshvaran, Deepak; Nikolka, Mark; Charmet, Jerome; Spalek, Leszek J.; Gicevicius, Mindaugas; Zhang, Youcheng; Schweicher, Guillaume; Howe, Duncan J.; Ursel, Sarah; Armitage, John; Dimov, Ivan B.; Kraft, Ulrike; Zhang, Weimin; Alsufyani, Maryam; Mcculloch, Iain; Owens, Roisin M.; Claesson, Per M.; Knowles, Tuomas P. J.; Sirringhaus, Henning
Effects of Processing-Induced Contamination on Organic Electronic Devices Journal Article
In: SMALL METHODS, 2023, ISSN: 2366-9608.
@article{WOS:001057448200001,
title = {Effects of Processing-Induced Contamination on Organic Electronic
Devices},
author = {Dimitrios Simatos and Ian E. Jacobs and Illia Dobryden and Malgorzata Nguyen and Achilleas Savva and Deepak Venkateshvaran and Mark Nikolka and Jerome Charmet and Leszek J. Spalek and Mindaugas Gicevicius and Youcheng Zhang and Guillaume Schweicher and Duncan J. Howe and Sarah Ursel and John Armitage and Ivan B. Dimov and Ulrike Kraft and Weimin Zhang and Maryam Alsufyani and Iain Mcculloch and Roisin M. Owens and Per M. Claesson and Tuomas P. J. Knowles and Henning Sirringhaus},
doi = {10.1002/smtd.202300476},
issn = {2366-9608},
year = {2023},
date = {2023-09-01},
journal = {SMALL METHODS},
publisher = {WILEY-V C H VERLAG GMBH},
address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY},
abstract = {Organic semiconductors are a family of pi-conjugated compounds used in
many applications, such as displays, bioelectronics, and
thermoelectrics. However, their susceptibility to processing-induced
contamination is not well understood. Here, it is shown that many
organic electronic devices reported so far may have been unintentionally
contaminated, thus affecting their performance, water uptake, and thin
film properties. Nuclear magnetic resonance spectroscopy is used to
detect and quantify contaminants originating from the glovebox
atmosphere and common laboratory consumables used during device
fabrication. Importantly, this in-depth understanding of the sources of
contamination allows the establishment of clean fabrication protocols,
and the fabrication of organic field effect transistors (OFETs) with
improved performance and stability. This study highlights the role of
unintentional contaminants in organic electronic devices, and
demonstrates that certain stringent processing conditions need to be met
to avoid scientific misinterpretation, ensure device reproducibility,
and facilitate performance stability. The experimental procedures and
conditions used herein are typical of those used by many groups in the
field of solution-processed organic semiconductors. Therefore, the
insights gained into the effects of contamination are likely to be
broadly applicable to studies, not just of OFETs, but also of other
devices based on these materials.
The susceptibility of organic semiconductor devices to
processing-induced contamination is not well understood. Nuclear
magnetic resonance is used to identify contaminants originating from the
glovebox atmosphere and laboratory consumables (disposable needles,
plastic pipettes, and plastic syringes). After establishing rigorous
fabrication protocols, it is demonstrated that even small amounts of
contaminants affect the thin-film processing behavior and the electrical
properties of devices.image},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
many applications, such as displays, bioelectronics, and
thermoelectrics. However, their susceptibility to processing-induced
contamination is not well understood. Here, it is shown that many
organic electronic devices reported so far may have been unintentionally
contaminated, thus affecting their performance, water uptake, and thin
film properties. Nuclear magnetic resonance spectroscopy is used to
detect and quantify contaminants originating from the glovebox
atmosphere and common laboratory consumables used during device
fabrication. Importantly, this in-depth understanding of the sources of
contamination allows the establishment of clean fabrication protocols,
and the fabrication of organic field effect transistors (OFETs) with
improved performance and stability. This study highlights the role of
unintentional contaminants in organic electronic devices, and
demonstrates that certain stringent processing conditions need to be met
to avoid scientific misinterpretation, ensure device reproducibility,
and facilitate performance stability. The experimental procedures and
conditions used herein are typical of those used by many groups in the
field of solution-processed organic semiconductors. Therefore, the
insights gained into the effects of contamination are likely to be
broadly applicable to studies, not just of OFETs, but also of other
devices based on these materials.
The susceptibility of organic semiconductor devices to
processing-induced contamination is not well understood. Nuclear
magnetic resonance is used to identify contaminants originating from the
glovebox atmosphere and laboratory consumables (disposable needles,
plastic pipettes, and plastic syringes). After establishing rigorous
fabrication protocols, it is demonstrated that even small amounts of
contaminants affect the thin-film processing behavior and the electrical
properties of devices.image
Bhattacharjee, Subhajit; Guo, Chengzhi; Lam, Erwin; Holstein, Josephin M.; Pereira, Mariana Rangel; Pichler, Christian M.; Pornrungroj, Chanon; Rahaman, Motiar; Uekert, Taylor; Hollfelder, Florian; Reisner, Erwin
Chemoenzymatic Photoreforming: A Sustainable Approach for Solar Fuel Generation from Plastic Feedstocks Journal Article
In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol. 145, no. 37, pp. 20355-20364, 2023, ISSN: 0002-7863.
@article{WOS:001122170800001,
title = {Chemoenzymatic Photoreforming: A Sustainable Approach for Solar Fuel
Generation from Plastic Feedstocks},
author = {Subhajit Bhattacharjee and Chengzhi Guo and Erwin Lam and Josephin M. Holstein and Mariana Rangel Pereira and Christian M. Pichler and Chanon Pornrungroj and Motiar Rahaman and Taylor Uekert and Florian Hollfelder and Erwin Reisner},
doi = {10.1021/jacs.3c05486},
issn = {0002-7863},
year = {2023},
date = {2023-09-01},
journal = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY},
volume = {145},
number = {37},
pages = {20355-20364},
publisher = {AMER CHEMICAL SOC},
address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
abstract = {Plastic upcycling through catalytic transformations is an attractive
concept to valorize waste, but the clean and energy-efficient production
of high-value products from plastics remains challenging. Here, we
introduce chemoenzymatic photoreforming as a process coupling enzymatic
pretreatment and solar-driven reforming of polyester plastics under mild
temperatures and pH to produce clean H-2 and value-added chemicals.
Chemoenzymatic photoreforming demonstrates versatility in upcycling
polyester films and nanoplastics to produce H-2 at high yields reaching
similar to 10(3)-10(4) mu mol g(sub)(-1) and activities at >500 mu mol
g(cat)(-1) h(-1). Enzyme-treated plastics were also used as electron
donors for photocatalytic CO2-to-syngas conversion with a phosphonated
cobalt bis(terpyridine) catalyst immobilized on TiO2 nanoparticles
(TiO2|CotpyP). Finally, techno-economic analyses reveal that the
chemoenzymatic photoreforming approach has the potential to drastically
reduce H-2 production costs to levels comparable to market prices of H-2
produced from fossil fuels while maintaining low CO2-equivalent
emissions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
concept to valorize waste, but the clean and energy-efficient production
of high-value products from plastics remains challenging. Here, we
introduce chemoenzymatic photoreforming as a process coupling enzymatic
pretreatment and solar-driven reforming of polyester plastics under mild
temperatures and pH to produce clean H-2 and value-added chemicals.
Chemoenzymatic photoreforming demonstrates versatility in upcycling
polyester films and nanoplastics to produce H-2 at high yields reaching
similar to 10(3)-10(4) mu mol g(sub)(-1) and activities at >500 mu mol
g(cat)(-1) h(-1). Enzyme-treated plastics were also used as electron
donors for photocatalytic CO2-to-syngas conversion with a phosphonated
cobalt bis(terpyridine) catalyst immobilized on TiO2 nanoparticles
(TiO2|CotpyP). Finally, techno-economic analyses reveal that the
chemoenzymatic photoreforming approach has the potential to drastically
reduce H-2 production costs to levels comparable to market prices of H-2
produced from fossil fuels while maintaining low CO2-equivalent
emissions.
Loeto, Kagiso; Kusch, Gunnar; Ghosh, Saptarsi; Frentrup, Martin; Hinz, Alexander; Oliver, Rachel
Compositional Mapping of the AlGaN Alloy Composition in Graded Buffer Structures Using Cathodoluminescence Journal Article
In: PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, vol. 220, no. 16, SI, 2023, ISSN: 1862-6300.
@article{WOS:000963062500001,
title = {Compositional Mapping of the AlGaN Alloy Composition in Graded Buffer
Structures Using Cathodoluminescence},
author = {Kagiso Loeto and Gunnar Kusch and Saptarsi Ghosh and Martin Frentrup and Alexander Hinz and Rachel Oliver},
doi = {10.1002/pssa.202200830},
issn = {1862-6300},
year = {2023},
date = {2023-08-01},
journal = {PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE},
volume = {220},
number = {16, SI},
publisher = {WILEY-V C H VERLAG GMBH},
address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY},
abstract = {Herein, the use of cathodoluminescence (CL) hyperspectral mapping in the
quantification of the AlGaN alloy composition in graded buffer
structures is explored. The quantification takes advantage of the known
parabolic dependence of the AlGaN bandgap on the alloy composition
allowing the AlGaN near-band-edge (NBE) emission energy recorded from CL
to be converted to a composition. The proposed quantification method is
first applied to cleaved cross-sections of two nominally step-graded
AlGaN buffer structures each containing five AlGaN layers with different
compositions. By comparing the compositions obtained from CL to those
calculated using X-ray diffraction, a close agreement between values
from both techniques is observed. However, due to a change in the bowing
parameter, some deviation is observed for layers with compositions near
75%. The method is then applied to cleaved cross-sections of an AlGaN
buffer whose group III precursor flow molar ratio is varied linearly
throughout the growth. Herein, the hyperspectral nature of the CL
datasets is exploited such as to produce composition maps by converting
the relevant AlGaN-NBE emission energy at each pixel of the CL data to a
composition.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
quantification of the AlGaN alloy composition in graded buffer
structures is explored. The quantification takes advantage of the known
parabolic dependence of the AlGaN bandgap on the alloy composition
allowing the AlGaN near-band-edge (NBE) emission energy recorded from CL
to be converted to a composition. The proposed quantification method is
first applied to cleaved cross-sections of two nominally step-graded
AlGaN buffer structures each containing five AlGaN layers with different
compositions. By comparing the compositions obtained from CL to those
calculated using X-ray diffraction, a close agreement between values
from both techniques is observed. However, due to a change in the bowing
parameter, some deviation is observed for layers with compositions near
75%. The method is then applied to cleaved cross-sections of an AlGaN
buffer whose group III precursor flow molar ratio is varied linearly
throughout the growth. Herein, the hyperspectral nature of the CL
datasets is exploited such as to produce composition maps by converting
the relevant AlGaN-NBE emission energy at each pixel of the CL data to a
composition.
Gorgon, Sebastian; Lv, Kuo; Grune, Jeannine; Drummond, Bluebell H.; Myers, William K.; Londi, Giacomo; Ricci, Gaetano; Valverde, Danillo; Tonnele, Claire; Murto, Petri; Romanov, Alexander S.; Casanova, David; Dyakonov, Vladimir; Sperlich, Andreas; Beljonne, David; Olivier, Yoann; Li, Feng; Friend, Richard H.; Evans, Emrys W.
Reversible spin-optical interface in luminescent organic radicals Journal Article
In: NATURE, vol. 620, no. 7974, pp. 538+, 2023, ISSN: 0028-0836.
@article{WOS:001169143500006,
title = {Reversible spin-optical interface in luminescent organic radicals},
author = {Sebastian Gorgon and Kuo Lv and Jeannine Grune and Bluebell H. Drummond and William K. Myers and Giacomo Londi and Gaetano Ricci and Danillo Valverde and Claire Tonnele and Petri Murto and Alexander S. Romanov and David Casanova and Vladimir Dyakonov and Andreas Sperlich and David Beljonne and Yoann Olivier and Feng Li and Richard H. Friend and Emrys W. Evans},
doi = {10.1038/s41586-023-06222-1},
issn = {0028-0836},
year = {2023},
date = {2023-08-01},
journal = {NATURE},
volume = {620},
number = {7974},
pages = {538+},
publisher = {NATURE PORTFOLIO},
address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},
abstract = {Molecules present a versatile platform for quantum information
science(1,2) and are candidates for sensing and computation
applications(3,4). Robust spin-optical interfaces are key to harnessing
the quantum resources of materials(5). To date, carbon-based candidates
have been non-luminescent(6,7), which prevents optical readout via
emission. Here we report organic molecules showing both efficient
luminescence and near-unity generation yield of excited states with spin
multiplicity S > 1. This was achieved by designing an energy resonance
between emissive doublet and triplet levels, here on covalently coupled
tris(2,4,6-trichlorophenyl) methyl-carbazole radicals and anthracene. We
observed that the doublet photoexcitation delocalized onto the linked
acene within a few picoseconds and subsequently evolved to a pure
high-spin state (quartet for monoradical, quintet for biradical) of
mixed radical-triplet character near 1.8 eV. These high-spin states are
coherently addressable with microwaves even at 295 K, with optical
readout enabled by reverse intersystem crossing to emissive states.
Furthermore, for the biradical, on return to the ground state the
previously uncorrelated radical spins either side of the anthracene
shows strong spin correlation. Our approach simultaneously supports a
high efficiency of initialization, spin manipulations and light-based
readout at room temperature. The integration of luminescence and
high-spin states creates an organic materials platform for emerging
quantum technologies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
science(1,2) and are candidates for sensing and computation
applications(3,4). Robust spin-optical interfaces are key to harnessing
the quantum resources of materials(5). To date, carbon-based candidates
have been non-luminescent(6,7), which prevents optical readout via
emission. Here we report organic molecules showing both efficient
luminescence and near-unity generation yield of excited states with spin
multiplicity S > 1. This was achieved by designing an energy resonance
between emissive doublet and triplet levels, here on covalently coupled
tris(2,4,6-trichlorophenyl) methyl-carbazole radicals and anthracene. We
observed that the doublet photoexcitation delocalized onto the linked
acene within a few picoseconds and subsequently evolved to a pure
high-spin state (quartet for monoradical, quintet for biradical) of
mixed radical-triplet character near 1.8 eV. These high-spin states are
coherently addressable with microwaves even at 295 K, with optical
readout enabled by reverse intersystem crossing to emissive states.
Furthermore, for the biradical, on return to the ground state the
previously uncorrelated radical spins either side of the anthracene
shows strong spin correlation. Our approach simultaneously supports a
high efficiency of initialization, spin manipulations and light-based
readout at room temperature. The integration of luminescence and
high-spin states creates an organic materials platform for emerging
quantum technologies.
Ye, Chumei; McHugh, Lauren N.; Chen, Celia; Dutton, Sian E.; Bennett, Thomas D.
Glass Formation in Hybrid Organic-Inorganic Perovskites Journal Article
In: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, vol. 62, no. 28, 2023, ISSN: 1433-7851.
@article{WOS:000977825100001,
title = {Glass Formation in Hybrid Organic-Inorganic Perovskites},
author = {Chumei Ye and Lauren N. McHugh and Celia Chen and Sian E. Dutton and Thomas D. Bennett},
doi = {10.1002/anie.202302406},
issn = {1433-7851},
year = {2023},
date = {2023-07-01},
journal = {ANGEWANDTE CHEMIE-INTERNATIONAL EDITION},
volume = {62},
number = {28},
publisher = {WILEY-V C H VERLAG GMBH},
address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY},
abstract = {Crystalline materials have governed the development of hybrid
organic-inorganic perovskites (HOIPs), giving rise to a variety of
fascinating applications such as solar cells and optoelectronic devices.
With increasing interest in non-crystalline systems, the glassy state of
HOIPs has recently been identified. Here, the basic building blocks of
crystalline HOIPs appear to be retained, though their glasses lack
long-range periodic order. The emerging family of glasses formed from
HOIPs exhibits diverse properties, complementary to their crystalline
state. This mini review describes the chemical diversity of both
three-dimensional and two-dimensional crystalline HOIPs and demonstrates
how glasses are produced from these materials. Specifically, current
achievements in melt-quenched glasses formed from HOIPs are highlighted.
We conclude with our perspective on the future of this new family of
materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
organic-inorganic perovskites (HOIPs), giving rise to a variety of
fascinating applications such as solar cells and optoelectronic devices.
With increasing interest in non-crystalline systems, the glassy state of
HOIPs has recently been identified. Here, the basic building blocks of
crystalline HOIPs appear to be retained, though their glasses lack
long-range periodic order. The emerging family of glasses formed from
HOIPs exhibits diverse properties, complementary to their crystalline
state. This mini review describes the chemical diversity of both
three-dimensional and two-dimensional crystalline HOIPs and demonstrates
how glasses are produced from these materials. Specifically, current
achievements in melt-quenched glasses formed from HOIPs are highlighted.
We conclude with our perspective on the future of this new family of
materials.
Murto, Petri; Chowdhury, Rituparno; Gorgon, Sebastian; Guo, Erjuan; Zeng, Weixuan; Li, Biwen; Sun, Yuqi; Francis, Haydn; Friend, Richard H.; Bronstein, Hugo
Mesitylated trityl radicals, a platform for doublet emission: symmetry breaking, charge-transfer states and conjugated polymers Journal Article
In: NATURE COMMUNICATIONS, vol. 14, no. 1, 2023.
@article{WOS:001029450400013,
title = {Mesitylated trityl radicals, a platform for doublet emission: symmetry
breaking, charge-transfer states and conjugated polymers},
author = {Petri Murto and Rituparno Chowdhury and Sebastian Gorgon and Erjuan Guo and Weixuan Zeng and Biwen Li and Yuqi Sun and Haydn Francis and Richard H. Friend and Hugo Bronstein},
doi = {10.1038/s41467-023-39834-2},
year = {2023},
date = {2023-07-01},
journal = {NATURE COMMUNICATIONS},
volume = {14},
number = {1},
publisher = {NATURE PORTFOLIO},
address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},
abstract = {Neutral & pi;-radicals have potential for use as light emitters in
optoelectronic devices due to the absence of energetically low-lying
non-emissive states. Here, we report a defect-free synthetic methodology
via mesityl substitution at the para-positions of
tris(2,4,6-trichlorophenyl)methyl radical. These materials reveal a
number of novel optoelectronic properties. Firstly, mesityl substituted
radicals show strongly enhanced photoluminescence arising from symmetry
breaking in the excited state. Secondly, photoexcitation of thin films
of 8 wt% radical in 4,4'-bis(carbazol-9-yl)-1,1'-biphenyl host matrix
produces long lived (in the order of microseconds) intermolecular charge
transfer states, following hole transfer to the host, that can show
unexpectedly efficient red-shifted emission. Thirdly, covalent
attachment of carbazole into the mesitylated radical gives very high
photoluminescence yield of 93% in 4,4'-bis(carbazol-9-yl)-1,1'-biphenyl
films and light-emitting diodes with maximum external quantum efficiency
of 28% at a wavelength of 689 nm. Fourthly, a main-chain copolymer of
the mesitylated radical and 9,9-dioctyl-9H-fluorene shows red-shifted
emission beyond 800 nm.
Neutral & pi;-radicals are potential emitters for optoelectronic
devices due to the absence of energetically low-lying non-emissive
states. Here, the authors report mesityl-substituted
tris(2,4,6-trichlorophenyl)methyl radicals and achieve maximum device
efficiency of 28% at a wavelength of 689 nm.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
optoelectronic devices due to the absence of energetically low-lying
non-emissive states. Here, we report a defect-free synthetic methodology
via mesityl substitution at the para-positions of
tris(2,4,6-trichlorophenyl)methyl radical. These materials reveal a
number of novel optoelectronic properties. Firstly, mesityl substituted
radicals show strongly enhanced photoluminescence arising from symmetry
breaking in the excited state. Secondly, photoexcitation of thin films
of 8 wt% radical in 4,4'-bis(carbazol-9-yl)-1,1'-biphenyl host matrix
produces long lived (in the order of microseconds) intermolecular charge
transfer states, following hole transfer to the host, that can show
unexpectedly efficient red-shifted emission. Thirdly, covalent
attachment of carbazole into the mesitylated radical gives very high
photoluminescence yield of 93% in 4,4'-bis(carbazol-9-yl)-1,1'-biphenyl
films and light-emitting diodes with maximum external quantum efficiency
of 28% at a wavelength of 689 nm. Fourthly, a main-chain copolymer of
the mesitylated radical and 9,9-dioctyl-9H-fluorene shows red-shifted
emission beyond 800 nm.
Neutral & pi;-radicals are potential emitters for optoelectronic
devices due to the absence of energetically low-lying non-emissive
states. Here, the authors report mesityl-substituted
tris(2,4,6-trichlorophenyl)methyl radicals and achieve maximum device
efficiency of 28% at a wavelength of 689 nm.
Baikie, Tomi K. K.; Xiao, James; Drummond, Bluebell H. H.; Greenham, Neil C. C.; Rao, Akshay
Spatially Resolved Optical Efficiency Measurements of Luminescent Solar Concentrators Journal Article
In: ACS PHOTONICS, vol. 10, no. 8, pp. 2886-2893, 2023, ISSN: 2330-4022.
@article{WOS:001030476400001,
title = {Spatially Resolved Optical Efficiency Measurements of Luminescent Solar
Concentrators},
author = {Tomi K. K. Baikie and James Xiao and Bluebell H. H. Drummond and Neil C. C. Greenham and Akshay Rao},
doi = {10.1021/acsphotonics.3c00601},
issn = {2330-4022},
year = {2023},
date = {2023-07-01},
journal = {ACS PHOTONICS},
volume = {10},
number = {8},
pages = {2886-2893},
publisher = {AMER CHEMICAL SOC},
address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
abstract = {Luminescent solar concentrators (LSCs) are able to concentrateboth
direct and diffuse solar radiation, and this ability has ledto great
interest in using them to improve solar energy capture whencoupled to
traditional photovoltaics (PV). In principle, a large-areaLSC could
concentrate light onto a much smaller area of PV, thus reducingcosts or
enabling new architectures. However, LSCs suffer from variousoptical
losses which are hard to quantify using simple measurementsof power
conversion efficiency. Here, we show that spatially
resolvedphotoluminescence quantum efficiency measurements on large-area
LSCscan be used to resolve various loss processes such as
out-coupling,self-absorption via emitters, and self-absorption from the
LSC matrix.Further, these measurements allow for the extrapolation of
deviceperformance to arbitrarily large LSCs. Our results provide
insightinto the optimization of optical properties and guide the design
offuture LSCs for improved solar energy capture.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
direct and diffuse solar radiation, and this ability has ledto great
interest in using them to improve solar energy capture whencoupled to
traditional photovoltaics (PV). In principle, a large-areaLSC could
concentrate light onto a much smaller area of PV, thus reducingcosts or
enabling new architectures. However, LSCs suffer from variousoptical
losses which are hard to quantify using simple measurementsof power
conversion efficiency. Here, we show that spatially
resolvedphotoluminescence quantum efficiency measurements on large-area
LSCscan be used to resolve various loss processes such as
out-coupling,self-absorption via emitters, and self-absorption from the
LSC matrix.Further, these measurements allow for the extrapolation of
deviceperformance to arbitrarily large LSCs. Our results provide
insightinto the optimization of optical properties and guide the design
offuture LSCs for improved solar energy capture.
Jakob, Lukas A.; Deacon, William M.; Zhang, Yuan; Nijs, Bart; Pavlenko, Elena; Hu, Shu; Carnegie, Cloudy; Neuman, Tomas; Esteban, Ruben; Aizpurua, Javier; Baumberg, Jeremy J.
Giant optomechanical spring effect in plasmonic nano- and picocavities probed by surface-enhanced Raman scattering Journal Article
In: NATURE COMMUNICATIONS, vol. 14, no. 1, 2023.
@article{WOS:001089014900001,
title = {Giant optomechanical spring effect in plasmonic nano- and picocavities
probed by surface-enhanced Raman scattering},
author = {Lukas A. Jakob and William M. Deacon and Yuan Zhang and Bart Nijs and Elena Pavlenko and Shu Hu and Cloudy Carnegie and Tomas Neuman and Ruben Esteban and Javier Aizpurua and Jeremy J. Baumberg},
doi = {10.1038/s41467-023-38124-1},
year = {2023},
date = {2023-06-01},
journal = {NATURE COMMUNICATIONS},
volume = {14},
number = {1},
publisher = {NATURE PORTFOLIO},
address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},
abstract = {Molecular vibrations couple to visible light only weakly, have small
mutual interactions, and hence are often ignored for non-linear optics.
Here we show the extreme confinement provided by plasmonic nano- and
pico-cavities can sufficiently enhance optomechanical coupling so that
intense laser illumination drastically softens the molecular bonds. This
optomechanical pumping regime produces strong distortions of the Raman
vibrational spectrum related to giant vibrational frequency shifts from
an optical spring effect which is hundred-fold larger than in
traditional cavities. The theoretical simulations accounting for the
multimodal nanocavity response and near-field-induced collective phonon
interactions are consistent with the experimentally-observed non-linear
behavior exhibited in the Raman spectra of nanoparticle-on-mirror
constructs illuminated by ultrafast laser pulses. Further, we show
indications that plasmonic picocavities allow us to access the optical
spring effect in single molecules with continuous illumination. Driving
the collective phonon in the nanocavity paves the way to control
reversible bond softening, as well as irreversible chemistry.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
mutual interactions, and hence are often ignored for non-linear optics.
Here we show the extreme confinement provided by plasmonic nano- and
pico-cavities can sufficiently enhance optomechanical coupling so that
intense laser illumination drastically softens the molecular bonds. This
optomechanical pumping regime produces strong distortions of the Raman
vibrational spectrum related to giant vibrational frequency shifts from
an optical spring effect which is hundred-fold larger than in
traditional cavities. The theoretical simulations accounting for the
multimodal nanocavity response and near-field-induced collective phonon
interactions are consistent with the experimentally-observed non-linear
behavior exhibited in the Raman spectra of nanoparticle-on-mirror
constructs illuminated by ultrafast laser pulses. Further, we show
indications that plasmonic picocavities allow us to access the optical
spring effect in single molecules with continuous illumination. Driving
the collective phonon in the nanocavity paves the way to control
reversible bond softening, as well as irreversible chemistry.
Haataja, Johannes S. S.; Jacucci, Gianni; Parton, Thomas G. G.; Schertel, Lukas; Vignolini, Silvia
Topological invariance in whiteness optimisation Journal Article
In: COMMUNICATIONS PHYSICS, vol. 6, no. 1, 2023, ISSN: 2399-3650.
@article{WOS:001002627600002,
title = {Topological invariance in whiteness optimisation},
author = {Johannes S. S. Haataja and Gianni Jacucci and Thomas G. G. Parton and Lukas Schertel and Silvia Vignolini},
doi = {10.1038/s42005-023-01234-9},
issn = {2399-3650},
year = {2023},
date = {2023-06-01},
journal = {COMMUNICATIONS PHYSICS},
volume = {6},
number = {1},
publisher = {NATURE PORTFOLIO},
address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},
abstract = {Maximizing the scattering of visible light within disordered
nano-structured materials is essential for commercial applications such
as brighteners, while also testing our fundamental understanding of
light-matter interactions. The progress in the research field has been
hindered by the lack of understanding how different structural features
contribute to the scattering properties. Here we undertake a systematic
investigation of light scattering in correlated disordered structures.
We demonstrate that the scattering efficiency of disordered systems is
mainly determined by topologically invariant features, such as the
filling fraction and correlation length, and residual variations are
largely accounted by the surface-averaged mean curvature of the systems.
Optimal scattering efficiency can thus be obtained from a broad range of
disordered structures, especially when structural anisotropy is included
as a parameter. These results suggest that any disordered system can be
optimised for whiteness and give comparable performance, which has
far-reaching consequences for the industrial use of low-index materials
for optical scattering.
Investigation on how to produce brilliant whiteness using disordered low
refractive index materials have strongly focused on specific biological
examples such as the white beetle scale structures. In this work, the
authors demonstrate that brilliant whiteness can achieved regardless of
the disordered topology by tuning a handful of parameters.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
nano-structured materials is essential for commercial applications such
as brighteners, while also testing our fundamental understanding of
light-matter interactions. The progress in the research field has been
hindered by the lack of understanding how different structural features
contribute to the scattering properties. Here we undertake a systematic
investigation of light scattering in correlated disordered structures.
We demonstrate that the scattering efficiency of disordered systems is
mainly determined by topologically invariant features, such as the
filling fraction and correlation length, and residual variations are
largely accounted by the surface-averaged mean curvature of the systems.
Optimal scattering efficiency can thus be obtained from a broad range of
disordered structures, especially when structural anisotropy is included
as a parameter. These results suggest that any disordered system can be
optimised for whiteness and give comparable performance, which has
far-reaching consequences for the industrial use of low-index materials
for optical scattering.
Investigation on how to produce brilliant whiteness using disordered low
refractive index materials have strongly focused on specific biological
examples such as the white beetle scale structures. In this work, the
authors demonstrate that brilliant whiteness can achieved regardless of
the disordered topology by tuning a handful of parameters.
Zhang, Qi; Toprakcioglu, Zenon; Jayaram, Akhila K.; Guo, Guangsheng; Wang, Xiayan; Knowles, Tuomas P. J.
Formation of Protein Nanoparticles in Microdroplet Flow Reactors Journal Article
In: ACS NANO, vol. 17, no. 12, pp. 11335-11344, 2023, ISSN: 1936-0851.
@article{WOS:001006190300001,
title = {Formation of Protein Nanoparticles in Microdroplet Flow Reactors},
author = {Qi Zhang and Zenon Toprakcioglu and Akhila K. Jayaram and Guangsheng Guo and Xiayan Wang and Tuomas P. J. Knowles},
doi = {10.1021/acsnano.3c00107},
issn = {1936-0851},
year = {2023},
date = {2023-06-01},
journal = {ACS NANO},
volume = {17},
number = {12},
pages = {11335-11344},
publisher = {AMER CHEMICAL SOC},
address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
abstract = {Nanoparticlesare increasingly being used for biological
applications,such as drug delivery and gene transfection. Different
biologicaland bioinspired building blocks have been used for generating
suchparticles, including lipids and synthetic polymers. Proteins are
anattractive class of material for such applications due to their
excellentbiocompatibility, low immunogenicity, and self-assembly
characteristics.Stable, controllable, and homogeneous formation of
protein nanoparticles,which is key to successfully delivering cargo
intracellularly, hasbeen challenging to achieve using conventional
methods. In order toaddress this issue, we employed droplet
microfluidics and utilizedthe characteristic of rapid and continuous
mixing within microdropletsin order to produce highly monodisperse
protein nanoparticles. Weexploit the naturally occurring vortex flows
within microdropletsto prevent nanoparticle aggregation following
nucleation, resultingin systematic control over the particle size and
monodispersity. Throughcombination of simulation and experiment, we find
that the internalvortex velocity within microdroplets determines the
uniformity ofthe protein nanoparticles, and by varying parameters such
as proteinconcentration and flow rates, we are able to finely tune
nanoparticledimensional properties. Finally, we show that our
nanoparticles arehighly biocompatible with HEK-293 cells, and through
confocal microscopy,we determine that the nanoparticles fully enter into
the cell withalmost all cells containing them. Due to the high
throughput of themethod of production and the level of control afforded,
we believethat the approach described in this study for generating
monodisperseprotein-based nanoparticles has the potential for
intracellular drugdelivery or for gene transfection in the future.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
applications,such as drug delivery and gene transfection. Different
biologicaland bioinspired building blocks have been used for generating
suchparticles, including lipids and synthetic polymers. Proteins are
anattractive class of material for such applications due to their
excellentbiocompatibility, low immunogenicity, and self-assembly
characteristics.Stable, controllable, and homogeneous formation of
protein nanoparticles,which is key to successfully delivering cargo
intracellularly, hasbeen challenging to achieve using conventional
methods. In order toaddress this issue, we employed droplet
microfluidics and utilizedthe characteristic of rapid and continuous
mixing within microdropletsin order to produce highly monodisperse
protein nanoparticles. Weexploit the naturally occurring vortex flows
within microdropletsto prevent nanoparticle aggregation following
nucleation, resultingin systematic control over the particle size and
monodispersity. Throughcombination of simulation and experiment, we find
that the internalvortex velocity within microdroplets determines the
uniformity ofthe protein nanoparticles, and by varying parameters such
as proteinconcentration and flow rates, we are able to finely tune
nanoparticledimensional properties. Finally, we show that our
nanoparticles arehighly biocompatible with HEK-293 cells, and through
confocal microscopy,we determine that the nanoparticles fully enter into
the cell withalmost all cells containing them. Due to the high
throughput of themethod of production and the level of control afforded,
we believethat the approach described in this study for generating
monodisperseprotein-based nanoparticles has the potential for
intracellular drugdelivery or for gene transfection in the future.
Oakes, G. A.; Peri, L.; Cochrane, L.; Martins, F.; Hutin, L.; Bertrand, B.; Vinet, M.; Saiz, A. Gomez; Ford, C. J. B.; Smith, C. G.; Gonzalez-Zalba, M. F.
Quantum Dot-Based Frequency Multiplier Journal Article
In: PRX QUANTUM, vol. 4, no. 2, 2023.
@article{WOS:001019518200001,
title = {Quantum Dot-Based Frequency Multiplier},
author = {G. A. Oakes and L. Peri and L. Cochrane and F. Martins and L. Hutin and B. Bertrand and M. Vinet and A. Gomez Saiz and C. J. B. Ford and C. G. Smith and M. F. Gonzalez-Zalba},
doi = {10.1103/PRXQuantum.4.020346},
year = {2023},
date = {2023-06-01},
journal = {PRX QUANTUM},
volume = {4},
number = {2},
publisher = {AMER PHYSICAL SOC},
address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},
abstract = {Silicon offers the enticing opportunity to integrate hybrid
quantum-classical computing systems on a single platform. For qubit
control and readout, high-frequency signals are required. Therefore,
devices that can facilitate its generation are needed. Here, we present
a quantum dot-based radio-frequency multiplier operated at cryogenic
temperatures. The device is based on the nonlinear capacitance-voltage
character-istics of quantum dot systems arising from their
low-dimensional density of states. We implement the multiplier in a
multigate silicon-nanowire transistor using two complementary device
configurations: a single quantum dot coupled to a charge reservoir and a
coupled double quantum dot. We study the har-monic voltage conversion as
a function of the energy detuning, the multiplication factor, and the
harmonic phase noise and find near ideal performance up to a
multiplication factor of 10. Our results demon-strate a method for
high-frequency conversion that could be readily integrated into
silicon-based quantum computing systems and be applied to other
semiconductors.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
quantum-classical computing systems on a single platform. For qubit
control and readout, high-frequency signals are required. Therefore,
devices that can facilitate its generation are needed. Here, we present
a quantum dot-based radio-frequency multiplier operated at cryogenic
temperatures. The device is based on the nonlinear capacitance-voltage
character-istics of quantum dot systems arising from their
low-dimensional density of states. We implement the multiplier in a
multigate silicon-nanowire transistor using two complementary device
configurations: a single quantum dot coupled to a charge reservoir and a
coupled double quantum dot. We study the har-monic voltage conversion as
a function of the energy detuning, the multiplication factor, and the
harmonic phase noise and find near ideal performance up to a
multiplication factor of 10. Our results demon-strate a method for
high-frequency conversion that could be readily integrated into
silicon-based quantum computing systems and be applied to other
semiconductors.