Imperial College London

Professor David J. Payne

Faculty of EngineeringDepartment of Materials

Professor of Materials Chemistry
 
 
 
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Contact

 

+44 (0)20 7594 2585d.payne Website

 
 
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Location

 

2.09Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

109 results found

Moss B, Wang Q, Butler K, Grau-Crespo R, Selim S, Regoutz A, Hisatomi T, Godin R, Payne D, Kafizas A, Domen K, Steier L, Durrant Jet al., 2021, Linking in situ charge accumulation to electronic structure in doped SrTiO3 reveals design principles for hydrogen-evolving photocatalysts, Nature Materials, Vol: 20, Pages: 511-517, ISSN: 1476-1122

Recently, high solar-to-hydrogen efficiencies were demonstrated using La and Rh co-doped SrTiO3 (La,Rh:SrTiO3) incorporated into a low-cost and scalable Z-scheme device, known as a photocatalyst sheet. However, the unique properties that enable La,Rh:SrTiO3 to support this impressive performance are not fully understood. Combining in situ spectroelectrochemical measurements with density functional theory and photoelectron spectroscopy produces a depletion model of Rh:SrTiO3 and La,Rh:SrTiO3 photocatalyst sheets. This reveals remarkable properties, such as deep flatband potentials (+2 V versus the reversible hydrogen electrode) and a Rh oxidation state dependent reorganization of the electronic structure, involving the loss of a vacant Rh 4d mid-gap state. This reorganization enables Rh:SrTiO3 to be reduced by co-doping without compromising the p-type character. In situ time-resolved spectroscopies show that the electronic structure reorganization induced by Rh reduction controls the electron lifetime in photocatalyst sheets. In Rh:SrTiO3, enhanced lifetimes can only be obtained at negative applied potentials, where the complete Z-scheme operates inefficiently. La co-doping fixes Rh in the 3+ state, which results in long-lived photogenerated electrons even at very positive potentials (+1 V versus the reversible hydrogen electrode), in which both components of the complete device operate effectively. This understanding of the role of co-dopants provides a new insight into the design principles for water-splitting devices based on bandgap-engineered metal oxides.

Journal article

Isakov I, Faber H, Mottram AD, Das S, Grell M, Regoutz A, Kilmurray R, McLachlan MA, Payne DJ, Anthopoulos TDet al., 2020, Quantum Confinement and Thickness-Dependent Electron Transport in Solution-Processed In(2)O(3)Transistors, ADVANCED ELECTRONIC MATERIALS, Vol: 6, ISSN: 2199-160X

Journal article

Cali E, Kerherve G, Naufal F, Kousi K, Neagu D, Papaioannou EI, Thomas MP, Guiton BS, Metcalfe IS, Irvine JTS, Payne DJet al., 2020, Exsolution of catalytically active iridium nanoparticles from strontium titanate, ACS Applied Materials and Interfaces, Vol: 12, Pages: 37444-37453, ISSN: 1944-8244

The search for new functional materials that combine high stability and efficiency with reasonable cost and ease of synthesis is critical for their use in renewable energy applications. Specifically in catalysis, nanoparticles, with their high surface-to-volume ratio, can overcome the cost implications associated with otherwise having to use large amounts of noble metals. However, commercialized materials, that is, catalytic nanoparticles deposited on oxide supports, often suffer from loss of activity because of coarsening and carbon deposition during operation. Exsolution has proven to be an interesting strategy to overcome such issues. Here, the controlled emergence, or exsolution, of faceted iridium nanoparticles from a doped SrTiO3 perovskite is reported and their growth preliminary probed by in situ electron microscopy. Upon reduction of SrIr0.005Ti0.995O3, the generated nanoparticles show embedding into the oxide support, therefore preventing agglomeration and subsequent catalyst degradation. The advantages of this approach are the extremely low noble metal amount employed (∼0.5% weight) and the catalytic activity reported during CO oxidation tests, where the performance of the exsolved SrIr0.005Ti0.995O3 is compared to the activity of a commercial catalyst with 1% loading (1% Ir/Al2O3). The high activity obtained with such low doping shows the possibility of scaling up this new catalyst, reducing the high cost associated with iridium-based materials.

Journal article

Mielewczyk-Gryn A, Wachowski S, Witkowska A, Dzierzgowski K, Skubida W, Swierczek K, Regoutz A, Payne DJ, Hull S, Zhang H, Abrahams I, Gazda Met al., 2020, Antimony substituted lanthanum orthoniobate proton conductor - Structure and electronic properties, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Vol: 103, Pages: 6575-6585, ISSN: 0002-7820

Journal article

Kousi K, Neagu D, Bekris L, Cali E, Kerherve G, Papaioannou E, Payne DJ, Metcalfe ISet al., 2020, Low temperature methane conversion with perovskite-supportedexo/endo-particles, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 8, Pages: 12406-12417, ISSN: 2050-7488

Journal article

Ryan PTP, Lalaguna PL, Haag F, Braim MM, Ding P, Payne DJ, Barth J, Lee T-L, Woodruff DP, Allegretti F, Duncan DAet al., 2020, Validation of the inverted adsorption structure for free-base tetraphenyl porphyrin on Cu(111), CHEMICAL COMMUNICATIONS, Vol: 56, Pages: 3681-3684, ISSN: 1359-7345

Journal article

Jakub Z, Hulva J, Ryan PTP, Duncan DAA, Payne DJJ, Bliem R, Ulreich M, Hofegger P, Kraushofer F, Meier M, Schmid M, Diebold U, Parkinson GSSet al., 2020, Adsorbate-induced structural evolution changes the mechanism of CO oxidation on a Rh/Fe3O4(001) model catalyst, NANOSCALE, Vol: 12, Pages: 5866-5875, ISSN: 2040-3364

Journal article

Bigi C, Orgiani P, Slawinska J, Fujii J, Irvine JT, Picozzi S, Panaccione G, Vobornik I, Rossi G, Payne D, Borgatti Fet al., 2020, Direct insight into the band structure of SrNbO3, PHYSICAL REVIEW MATERIALS, Vol: 4, ISSN: 2475-9953

Journal article

Lin C-T, Lee J, Kim J, Macdonald TJ, Ngiam J, Xu B, Daboczi M, Xu W, Pont S, Park B, Kang H, Kim J-S, Payne DJ, Lee K, Durrant JR, McLachlan MAet al., 2020, Origin of open-circuit voltage enhancements in planar Perovskite solar cells induced by addition of bulky organic cations, Advanced Functional Materials, Vol: 30, ISSN: 1616-301X

The origin of performance enhancements in p‐i‐n perovskite solar cells (PSCs) when incorporating low concentrations of the bulky cation 1‐naphthylmethylamine (NMA) are discussed. A 0.25 vol % addition of NMA increases the open circuit voltage (Voc) of methylammonium lead iodide (MAPbI3) PSCs from 1.06 to 1.16 V and their power conversion efficiency (PCE) from 18.7% to 20.1%. X‐ray photoelectron spectroscopy and low energy ion scattering data show NMA is located at grain surfaces, not the bulk. Scanning electron microscopy shows combining NMA addition with solvent assisted annealing creates large grains that span the active layer. Steady state and transient photoluminescence data show NMA suppresses non‐radiative recombination resulting from charge trapping, consistent with passivation of grain surfaces. Increasing the NMA concentration reduces device short‐circuit current density and PCE, also suppressing photoluminescence quenching at charge transport layers. Both Voc and PCE enhancements are observed when bulky cations (phenyl(ethyl/methyl)ammonium) are incorporated, but not smaller cations (Cs/MA)—indicating size is a key parameter. Finally, it demonstrates that NMA also enhances mixed iodide/bromide wide bandgap PSCs (Voc of 1.22 V with a 1.68 eV bandgap). The results demonstrate a facile approach to maximizing Voc and provide insights into morphological control and charge carrier dynamics induced by bulky cations in PSCs.

Journal article

Ryan PTP, Meier M, Jakub Z, Balajka J, Hulva J, Payne DJ, Lee T-L, Franchini C, Allegretti F, Parkinson GS, Duncan DAet al., 2020, Probing structural changes upon carbon monoxide coordination to single metal adatoms, JOURNAL OF CHEMICAL PHYSICS, Vol: 152, ISSN: 0021-9606

Journal article

Kim N, Thomas MR, Bergholt MS, Pence IJ, Seong H, Charchar P, Todorova N, Nagelkerke A, Belessiotis-Richard A, Payne D, Gelmi A, Yarovsky I, Stevens Met al., 2020, Surface enhanced raman scattering artificial nose for high dimensionality fingerprinting, Nature Communications, Vol: 11, ISSN: 2041-1723

Label-free surface-enhanced Raman spectroscopy (SERS) can interrogate systems by directly fingerprinting its components’ unique physicochemical properties. In complex biological systemshowever, this can yield highly overlapping spectra that hinder sample identification. Here, we present an artificial-nose inspired SERS fingerprinting approach where spectral data is obtained as a function of sensor surface chemical functionality. Supported by molecular dynamics modelling, we show that mildly selective self-assembled monolayers can influence the strength and configuration in which analytes interact with plasmonic surfaces, diversifying the resulting SERS fingerprints. Since each sensor generates a modulated signature, the implicit value of increasing the dimensionality of datasets is shown using cell lysates for all possible combinations of up to 9 fingerprints. Reliable improvements in mean discriminatory accuracy towards 100% is achieved with each additional surface functionality. This arrayed label-free platform illustrates the wide-ranging potential of high dimensionality artificial-nose based sensing systems for more reliable assessment of complex biological matrices.

Journal article

Mielewczyk-Gryn A, Wachowski S, Przesniak-Welenc M, Dzierzgowski K, Regoutz A, Payne DJ, Gazda Met al., 2019, Water uptake analysis of acceptor-doped lanthanum orthoniobates, Journal of Thermal Analysis and Calorimetry: an international forum for thermal studies, Vol: 138, Pages: 225-232, ISSN: 1588-2926

In this work, lanthanum orthoniobates doped with either antimony, calcium, or both have been synthesized and studied. The water uptake of the investigated materials has been analyzed by means of thermogravimetric studies. The results show the difference between the thermodynamics of hydration between the lanthanum orthoniobate system and other proton conducting ceramics. The relation between the water uptake and effective acceptor doping for the investigated system has been found, and the energetics of the water uptake relation are discussed.

Journal article

Fogarty R, Palgrave R, Bourne R, Handrup K, Villar I, Payne D, Hunt P, Lovelock KRJet al., 2019, Electron spectroscopy of ionic liquids: experimental identification of atomic orbital contributions to valence electronic structure, Physical Chemistry Chemical Physics, Vol: 21, Pages: 18893-18910, ISSN: 1463-9076

The atomic contributions to valence electronic structure for 37 ionic liquids (ILs) are identified using a combination of variable photon energy XPS, resonant Auger electron spectroscopy (RAES) and a subtraction...</p>

Journal article

Tan SY, Payne DJ, Hallett JP, Kelsall GHet al., 2019, Developments in electrochemical processes for recycling lead-acid batteries, Current Opinion in Electrochemistry, Vol: 16, Pages: 83-89, ISSN: 2451-9103

The lead-acid battery recycling industry is very well established, but the conventional pyrometallurgical processes are far from environmentally benign. Hence, recent developments of lead-acid battery recycling technologies have focused on low-temperature (electro-)hydrometallurgical processes, the subject of this review, covering modified electrolytes, improved reaction engineering, better reactor design and control of operating conditions.

Journal article

Twyman N, Tetzner K, Anthopoulos T, Payne D, Regoutz Aet al., 2019, Rapid photonic curing of solution-processed In2O3 layers on flexible substrates, Applied Surface Science, Vol: 479, Pages: 974-979, ISSN: 0169-4332

In2O3 is one of the most important semiconducting metal oxides primarily because of its wide band gap, high electron mobility and processing versatility. To this end, high-quality thin films of In2O3 can be prepared using scalable and inexpensive solution-based deposition methods, hence making it attractive for application in a number of emerging electronic applications. However, traditional solution processing often requires high temperature and lengthy annealing steps, making it impossible to use in combination with temperature-sensitive plastic substrates, which would be desired for numerous emerging flexible device applications. Here, rapid photonic curing of In2O3 layers is explored as an alternative to thermal annealing. Oxide thin films are successfully prepared on a range of substrates, including glass, polyimide, and polyethylene naphthalate. The effect of substrate and post-processing treatment on the morphology, surface chemistry, and electronic properties is investigated by atomic force microscopy and X-ray photoelectron spectroscopy. Systematic trends are identified, particularly in the degree of conversion of the precursor and its influence on the electronic structure.

Journal article

Robinson MDM, Oropeza FE, Cui M, Zhang KHL, Hohmann MV, Payne DJ, Egdell RG, Regoutz Aet al., 2019, Electronic structure of lanthanide-doped bismuth vanadates: A systematic study by x-ray photoelectron and optical spectroscopies, Journal of Physical Chemistry C, Vol: 123, Pages: 8484-8499, ISSN: 1932-7447

Monoclinic BiVO 4 has emerged in recent years as one of the most promising materials for photocatalytic evolution of oxygen under solar irradiation. However, it is in itself unable to phototcatalyze reduction of water to hydrogen due to the placement of the conduction band edge below the potential required for H 2 O/H 2 reduction. As a consequence, BiVO 4 only finds application in a hybrid system. Very recently, tetragonal lanthanide-doped BiVO 4 powders have been shown to be able to both reduce and to oxidize water under solar irradiation, but to date there has been no comprehensive study of the electronic properties of lanthanide-doped bismuth vanadates aimed at establishing the systematic trends in the electronic structure in traversing the lanthanide series. Here, the accessible family of lanthanide-doped BiVO 4 quaternary oxides of stoichiometry Bi 0.5 Ln 0.5 VO 4 (Ln = La to Lu, excluding Pm) has been studied by X-ray powder diffraction, X-ray photoemission spectroscopy, and diffuse reflectance optical spectroscopy. The compounds all adopt the tetragonal zircon structure, and lattice parameters decrease monotonically in traversing the lanthanide series. At the same time, there is an increased peak broadening in the diffraction patterns as the mismatch in ionic radius between Bi 3+ and the Ln 3+ ions increases across the series. Valence band X-ray photoemission spectra show that the final state 4f n-1 structure associated with ionization of lanthanide 4f n states is superimposed on the valence band structure of BiVO 4 in the quaternary materials: in the case of the Ce-, Pr- and Tb-doped BiVO 4 , 4f-related states appear above the top of the main valence band of BiVO 4 and account for the small bandgap in the Ce compound. In all cases, the 4f structure is characteristic of the lanthanide element in the Ln(III) oxidation state. Vanadium 2p and lanthanide 3d or 4d core level photoelectron spectra of those compounds where the lanthanide may in principle adopt a hig

Journal article

Leber R, Wilson L, Robaschik P, Inkpen M, Payne D, Long N, Albrecht T, Hirjibehedin C, Heutz Set al., 2019, Vacuum deposition of biferrocene thin films: growth strategies for stability and tuneable magnetism, 257th National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Conference paper

Regoutz A, Ganose AM, Blumenthal L, Schlueter C, Lee T-L, Kieslich G, Cheetham AK, Kerherve G, Huang Y-S, Chen R-S, Vinai G, Pincelli T, Panaccione G, Zhang KHL, Egdell RG, Lischner J, Scanlon DO, Payne DJet al., 2019, Insights into the electronic structure of OsO2 using soft and hard x-ray photoelectron spectroscopy in combination with density functional theory, Physical Review Materials, Vol: 3, ISSN: 2475-9953

Theory and experiment are combined to gain an understanding of the electronic properties of OsO2, a poorly studied metallic oxide that crystallizes in the rutile structure. Hard and soft valence-band x-ray photoemission spectra of OsO2 single crystals are in broad agreement with the results of density-functional-theory calculations, aside from a feature shifted to high binding energy of the conduction band. The energy shift corresponds to the conduction electron plasmon energy measured by reflection electron energy loss spectroscopy. The plasmon satellite is reproduced by many-body perturbation theory.

Journal article

Davies DW, Walsh A, Mudd JJ, McConville CF, Regoutz A, Kahk JM, Payne DJ, Dhanak VR, Hesp D, Pussi K, Lee T-L, Egdell RG, Zhang KHLet al., 2019, Identification of lone-pair surface states on indium oxide, Journal of Physical Chemistry C, Vol: 123, Pages: 1700-1709, ISSN: 1932-7447

Indium oxide is widely used as a transparent electrode in optoelectronic devices and as a photocatalyst with activity for reduction of CO2. However, very little is known about the structural and electronic properties of its surfaces, particularly those prepared under reducing conditions. In this report, directional “lone-pair” surface states associated with filled 5s2 orbitals have been identified on vacuum-annealed In2O3(111) through a combination of hard and soft X-ray photoemission spectroscopy and density functional theory calculations. The lone pairs reside on indium ad-atoms in a formal +1 oxidation state, each of which traps two electrons into a localized hybrid orbital protruding away from the surface and lying just above the valence band maximum in photoemission spectra. The third electron associated with the ad-atoms is delocalized into the conduction band, thus producing the surface electron accumulation layer identified previously on vacuum-annealed In2O3(111) (1 × 1) surfaces. The surface structure is further supported by low-energy electron diffraction, but there is no chemical shift in indium core level X-ray photoelectron spectra between surface In(I) ad-atoms and bulk In(III). The 5s2 lone pairs confer Lewis basicity on the surface In sites and may have a pronounced impact on the catalytic or photocatalytic activity of reduced In2O3.

Journal article

Regoutz A, Kerherve G, Villar-Garcia I, Williams CK, Payne DJet al., 2018, The influence of oxygen on the surface interaction between CO2 and copper studied by ambient pressure X-ray photoelectron spectroscopy, SURFACE SCIENCE, Vol: 677, Pages: 121-127, ISSN: 0039-6028

Journal article

Maher RC, Kerherve G, Payne DJ, Yue X, Connor PA, Irvine J, Cohen Let al., 2018, The reduction properties of M‐Doped (M=Zr, Gd) CeO2/YSZ scaffolds co‐infiltrated with nickel, Energy Technology, Vol: 6, Pages: 2045-2052, ISSN: 2194-4296

In recent years infiltration of materials into porous ceramic scaffolds has been shown to be an effective way of creating catalytically active components for solid oxide fuel cells (SOFCs). However, the redox properties of these novel structures are not well understood. Here, we use X‐ray photoelectron spectroscopy (XPS) and in‐situ Raman spectroscopy to investigate the oxidation properties of yttria‐stabilised zirconia (YSZ) scaffolds infiltrated with ceria (CeO2), gadolinium‐doped ceria (GDC) and zirconia‐doped ceria (ZDC), with and without Ni. XPS shows that doping ceria with zirconia increases the ratio of Ce3+ to Ce4+, while gadolinium doping results in a decrease of Ce3+. The presence of Ni increases the Ce3+/Ce4+ ratio for CeO2 and GDC, but had little effect on ZDC. We used the shift of the F2g Raman peak to monitor in‐situ, the oxidation state of ceria. In the as‐made compounds, we show that while the gadolinium and zirconium dopants significantly change the oxidation characteristics of ceria, the resulting materials are only significantly reduced above 500 °C when co‐infiltrated with Ni. In‐situ Raman monitoring during reduction as a function of temperature showed that while ZDC reduces much more readily than undoped ceria or GDC, the presence of Ni dominated the reduction dynamics.

Journal article

Connor PA, Yue X, Savaniu, Price R, Triantafyllou, Cassidy, Kerherve G, Payne DJ, Maher R, Cohen L, TOmov RI, Glowacki, Kumar, Irvine JTSet al., 2018, Tailoring SOFC electrode microstructures for improved performance, Advanced Energy Materials, Vol: 8, Pages: 1-20, ISSN: 1614-6832

The key technical challenges that fuel cell developers need to address are performance, durability, and cost. All three need to be achieved in parallel; however, there are often competitive tensions, e.g., performance is achieved at the expense of durability. Stability and resistance to degradation under prolonged operation are key parameters. There is considerable interest in developing new cathodes that are better able to function at lower temperature to facilitate low cost manufacture. For anodes, the ability of the solid oxide fuel cell (SOFC) to better utilize commonly available fuels at high efficiency, avoid coking and sulfur poisoning or resistance to oxidation at high utilization are all key. Optimizing a new electrode material requires considerable process development. The use of solution techniques to impregnate an already optimized electrode skeleton, offers a fast and efficient way to evaluate new electrode materials. It can also offer low cost routes to manufacture novel structures and to fine tune already known structures. Here impregnation methodologies are discussed, spectral and surface characterization are considered, and the recent efforts to optimize both cathode and anode functionalities are reviewed. Finally recent exemplifications are reviewed and future challenges and opportunities for the impregnation approach in SOFCs are explored.

Journal article

Ryan PTP, Jakub Z, Balajka J, Hulva J, Meier M, Kuechle JT, Blowey PJ, Thakur PK, Franchini C, Payne DJ, Woodruff DP, Rochford LA, Allegretti F, Lee T-L, Parkinson GS, Duncan DAet al., 2018, Direct measurement of Ni incorporation into Fe3O4(001), Physical Chemistry Chemical Physics, Vol: 20, Pages: 16469-16476, ISSN: 1463-9076

The normal incidence X-ray standing wave (NIXSW) technique has been used to follow the evolution of the adsorption geometry of Ni adatoms on the Fe3O4(001)-(√2 × √2)R45° surface as a function of temperature. Two primary surface region sites are identified: a bulk-continuation tetrahedral site and a sub-surface octahedral site, the latter site being preferred at higher annealing temperatures. The ease of incorporation is linked to the presence of subsurface cation vacancies in the (√2 × √2)R45° reconstruction and is consistent with the preference for octahedral coordination observed in the spinel compound NiFe2O4.

Journal article

Das PK, Slawinska J, Vobornik I, Fujii J, Regoutz A, Kahk JM, Scanlon DO, Morgan BJ, McGuinness C, Plekhanov E, Di Sante D, Huang Y-S, Chen R-S, Rossi G, Picozzi S, Branford WR, Panaccione G, Payne DJet al., 2018, Role of spin-orbit coupling in the electronic structure of IrO2, Physical Review Materials, Vol: 2, ISSN: 2475-9953

The delicate interplay of electronic charge, spin, and orbital degrees of freedom is in the heart of many novel phenomena across the transition metal oxide family. Here, by combining high-resolution angle-resolved photoemission spectroscopy and first principles calculations (with and without spin-orbit coupling), the electronic structure of the rutile binary iridate, IrO2, is investigated. The detailed study of electronic bands measured on a high-quality single crystalline sample and use of a wide range of photon energy provide a huge improvement over the previous studies. The excellent agreement between theory and experimental results shows that the single-particle DFT description of IrO2 band structure is adequate, without the need of invoking any treatment of correlation effects. Although many observed features point to a 3D nature of the electronic structure, clear surface effects are revealed. The discussion of the orbital character of the relevant bands crossing the Fermi level sheds light on spin-orbit-coupling-driven phenomena in this material, unveiling a spin-orbit-induced avoided crossing, a property likely to play a key role in its large spin Hall effect.

Journal article

Ballantyne AD, Hallett JP, Riley DJ, Shah N, Payne DJet al., 2018, Lead acid battery recycling for the twenty-first century, Royal Society Open Science, Vol: 5, Pages: 171368-171368, ISSN: 2054-5703

There is a growing need to develop novel processes to recover lead from end-of-life lead-acid batteries, due to increasing energy costs of pyrometallurgical lead recovery, the resulting CO2 emissions and the catastrophic health implications of lead exposure from lead-to-air emissions. To address these issues, we are developing an iono-metallurgical process, aiming to displace the pyrometallurgical process that has dominated lead production for millennia. The proposed process involves the dissolution of Pb salts into the deep eutectic solvent (DES) Ethaline 200, a liquid formed when a 1 : 2 molar ratio of choline chloride and ethylene glycol are mixed together. Once dissolved, the Pb can be recovered through electrodeposition and the liquid can then be recycled for further Pb recycling. Firstly, DESs are being used to dissolve the lead compounds (PbCO3, PbO, PbO2 and PbSO4) involved and their solubilities measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The resulting Pb2+ species are then reduced and electrodeposited as elemental lead at the cathode of an electrochemical cell; cyclic voltammetry and chronoamperometry are being used to determine the electrodeposition behaviour and mechanism. The electrodeposited films were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). We discuss the implications and opportunities of such processes.

Journal article

El-Shinawi H, Regoutz A, Payne DJ, Cussen EJ, Corr SAet al., 2018, NASICON LiM2(PO4)(3) electrolyte (M = Zr) and electrode (M = Ti) materials for all solid-state Li-ion batteries with high total conductivity and low interfacial resistance, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 6, Pages: 5296-5303, ISSN: 2050-7488

Journal article

Borgatti F, Berger JA, Ceolin D, Zhou JS, Kas JJ, Guzzo M, McConville CF, Offi F, Panaccione G, Regoutz A, Payne DJ, Rueff J-P, Bierwagen O, White ME, Speck JS, Gatti M, Egdell RGet al., 2018, Revisiting the origin of satellites in core-level photoemission of transparent conducting oxides: The case of &ITn&IT-doped SnO2, PHYSICAL REVIEW B, Vol: 97, ISSN: 2469-9950

Journal article

Wijeyasinghe N, Tsetseris L, Regoutz A, Sit WY, Fei Z, Du T, Wang X, Mclachlan MA, Vourlias G, Patsalas PA, Payne DJ, Heeney M, Anthopoulos TDet al., 2018, Copper (I) selenocyanate (CuSeCN) as a novel hole-transport layer for transistors, organic solar cells, and light-emitting diodes, Advanced Functional Materials, Vol: 28, ISSN: 1616-301X

The synthesis and characterization of copper (I) selenocyanate (CuSeCN) and its application as a solution-processable hole-transport layer (HTL) material in transistors, organic light-emitting diodes, and solar cells are reported. Density-functional theory calculations combined with X-ray photoelectron spectroscopy are used to elucidate the electronic band structure, density of states, and microstructure of CuSeCN. Solution-processed layers are found to be nanocrystalline and optically transparent ( > 94%), due to the large bandgap of ≥3.1 eV, with a valence band maximum located at -5.1 eV. Hole-transport analysis performed using field-effect measurements confirms the p-type character of CuSeCN yielding a hole mobility of 0.002 cm 2 V -1 s -1 . When CuSeCN is incorporated as the HTL material in organic light-emitting diodes and organic solar cells, the resulting devices exhibit comparable or improved performance to control devices based on commercially available poly(3,4-ethylenedioxythiophene):polystyrene sulfonate as the HTL. This is the first report on the semiconducting character of CuSeCN and it highlights the tremendous potential for further developments in the area of metal pseudohalides.

Journal article

Trantidou T, Regoutz A, Voon X, Payne D, Ces Oet al., 2018, A “cleanroom-free” and scalable manufacturing technology for the microfluidic generation of lipid-stabilized droplets and cell-sized multisomes, Sensors and Actuators B: Chemical, Vol: 267, Pages: 34-41, ISSN: 0925-4005

There is a growing demand to construct artificial biomimetic structures from the bottom-up using simple chemical components in a controlled and high-throughput way. These cell mimics are encapsulated by lipid membranes and can reconstitute biological machinery within them. To date, such synthetic cells based upon droplet microfluidics are fabricated using non-scalable, expensive and time-consuming strategies, and are thus restricted to small-scale in-house manufacturing. Here, we report a “cleanroom-free” and highly scalable microfluidic manufacturing technology based on dry film resists and multilayer lamination. The technology facilitates the controlled and high-throughput generation of stable and monodisperse droplets using anionic surfactants and more biologically relevant phospholipids. We demonstrate the versatility of this approach by selectively patterning the surface chemistry of the device, enabling the production of compartmentalized lipid structures based on droplet interface bilayers (multisomes). This technology has the potential to simultaneously unlock the widespread exploitation of microfluidics to chemists and synthetic biologists not having access to controlled production environments and facilitate low-cost (< £1) high-volume fabrication of self-contained disposable devices with minimum feature sizes of 30 μm. The associated material and equipment costs approach those of other deskilled prototyping technologies, such as 3D printing that have made the transition into the mainstream.

Journal article

Tomov RI, Mitchel-Williams TB, Maher R, Kerherve G, Cohen L, Payne DJ, Kumar RV, Glowacki BAet al., 2018, The synergistic effect of cobalt oxide and Gd-CeO₂ dual infiltration in LSCF/CGO cathodes, Journal of Materials Chemistry A, Vol: 6, Pages: 5071-5081, ISSN: 2050-7496

La0.6Sr0.4Co0.2Fe0.8O3 d/Ce0.9Gd0.1O1.9 composite cathodes were nano-engineered via “dual” inkjetprinting infiltration of nitrate salt solutions in a single step procedure. After calcination in air at 700 Cthe cathodes were decorated with Ce0.9Gd0.1O1.9 and CoxOy nanoparticles ( 20 nm in size). The effectsof the as-created nano-decoration on the electrochemical activity and the performance stability in theintermediate temperature range (500–700 C) were investigated. The nano-engineered microstructurewas found to extend the active three-phase boundary and to promote adsorption–dissociation–surfaceexchange reactions. Electrochemical impedance tests conducted on symmetric cells showeda reduction in the polarisation resistance of between 1.5 and 7.0 times depending on temperature (500–700 C). High-resolution X-ray photoelectron spectroscopy and in situ high temperature Ramanspectroscopy were used to study aging and thermal cycling effects on the cathodes' surface chemistry.Aging tests of the infiltrated electrodes up to 100 hours in air revealed an enhanced stability of thedecorated electrodes ascribed to the suppression of SrO surface segregation. This work demonstratedthat the sequence of infiltration of both inks introduces noticeable differences in the oxygen reductionreaction.

Journal article

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