A5003503768- Luminescence and Fluorescent Materials
- Dendrimers and Hyperbranched Polymers
- Organic Electronics and Photovoltaics
- Molecular Sensors and Ion Detection
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Conducting polymers and applications
- Machine Learning in Materials Science
- Organic Light-Emitting Diodes Research
- Solid-state spectroscopy and crystallography
- Nuclear Physics and Applications
- Catalysis and Oxidation Reactions
- Advanced NMR Techniques and Applications
- Zeolite Catalysis and Synthesis
- Energetic Materials and Combustion
- Perovskite Materials and Applications
- Crystal Structures and Properties
- Analytical Chemistry and Sensors
- Crystallography and molecular interactions
- Fuel Cells and Related Materials
- Gas Sensing Nanomaterials and Sensors
- Catalytic Processes in Materials Science
- Quantum, superfluid, helium dynamics
- High-pressure geophysics and materials
- Photoreceptor and optogenetics research
Rutherford Appleton Laboratory
2018-2025
ISIS Neutron and Muon Source
2025
Science and Technology Facilities Council
2018-2024
Chilton Medical Center
2021
Didcot Community Hospital
2021
Cranfield University
2017-2018
Defence Academy of the United Kingdom
2017-2018
The University of Queensland
2009-2016
Brisbane School of Theology
2015
The production of MOFs at large scale in a sustainable way is key if these materials are to be exploited for their promised widespread application. Much the published literature has focused on demonstrations preparation routes using difficult or expensive methodologies scale. One such MOF nano-zeolitic imidazolate framework-8 (ZIF-8) - material interest range possible applications. Work presented here shows how synthesis ZIF-8 can tracked by methods including X-ray diffraction, thermo...
We investigate the evolution of vertical morphology in a solution-processed P3HT/PCBM "bilayer" organic solar cell using combination techniques, including neutron reflectometry. By correlating device performance with active layer morphology, we establish that solution processed bilayer concept is misnomer and sequential processing an elegant way to make bulk heterojunction cells high efficiency.
Steady-state Stern−Volmer analysis is uniformly used to assess in solution the efficiency of a sensing molecule for particular analyte. We use combination steady-state and time-resolved photoluminescence (TRPL) determine underlying mechanisms by which fluorescent materials comprised fluorene-based chromophores sense nitro-based explosive analytes. The ability two first-generation dendrimers bifluorene-containing analytes was compared with chemically related polymer...
Abstract Understanding and controlling the morphology of donor/acceptor blends is critical for development solution processable organic solar cells. By crosslinking a poly(3‐ n ‐hexylthiophene‐2,5‐diyl) (P3HT) film we have been able to spin‐coat [6,6]‐phenyl‐C 61 ‐butyric acid methyl ester (PCBM) onto form structure that close bilayer, thus creating an ideal platform investigating interdiffusion in this model system. Neutron reflectometry (NR) demonstrates without any thermal treatment...
Abstract Optimising the balance between propene selectivity, propene/ethene ratio and catalytic stability unravelling explicit mechanism on formation of first carbon–carbon bond are challenging goals great importance in state-of-the-art methanol-to-olefin (MTO) research. We report a strategy to finely control nature active sites within pores commercial MFI-zeolites by incorporating tantalum(V) aluminium(III) centres into framework. The resultant TaAlS-1 zeolite exhibits simultaneously...
Abstract The combination of a heterogeneous catalyst operating within defined reactor comes the domain reaction engineering, which takes cognisance combined roles for both and to define overall operational system. One technique is demonstrating much promise in investigating engineering issues neutron imaging. skewed towards monitoring hydrogen hydrogenous species so, with being ubiquitous industrial organic chemistry penetrating power neutrons, imaging can monitor concentrations distributed...
Determining how analytes are sequestered into thin films is important for solid-state sensors that detect the presence of analyte by oxidative luminescence quenching. We show (230 +/- 30 A) and thick (750 50 a first-generation dendrimer comprised 2-ethylhexyloxy surface groups, biphenyl-based dendrons, 9,9,9',9'-tetra-n-propyl-2,2'-bifluorene core, can rapidly reversibly p-nitrotoluene For both photoluminescence (PL) quenched approximately 90% in 4 s, which much faster than reported...
Abstract Stable film morphology is critical for long‐term high performance organic light‐emitting diodes (OLEDs). Neutron reflectometry (NR) used to study the out‐of‐plane structure of blended thin films and multilayer structures comprising evaporated small molecules. It found that as‐prepared fac ‐tris(2‐phenylpyridyl)iridium(III) [Ir(ppy) 3 ] in 4,4′‐bis( N ‐carbazolyl)biphenyl (CBP) are uniformly mixed, but occurrence phase separation upon thermal annealing dependent on blend ratio. Films...
We present a study on three generations of fluorescent carbazole dendrimers that exhibit strong binding with nitroaromatic compounds accompanied by photoluminescence (PL) quenching, making them attractive sensing materials for the detection explosives such as 2,4,6-trinitrotoluene (TNT). The absorption and release vapors (deuterated) TNT analogue 4-nitrotoluene (pNT) from thin films were studied combination time-correlated neutron reflectometry PL spectroscopy. When saturated pNT was fully...
With a multitude of potential applications, poly(phosphine–borane)s are an interesting class polymer comprising main-group elements within the inorganic backbone. A new family primary alkylphosphine–borane polymers was synthesized by solvent-free rhodium-catalyzed dehydrocoupling reaction and characterized conventional chemicophysical techniques. The thermal stability is strongly affected size shape alkyl side chain with longer substituents imparting greater stability. show substantial...
In this paper, we use a combination of experiment and simulation to achieve enhanced levels synthetic control on the microstructure much-used binder material hydroxyl terminated polybutadiene (HTPB).
We compare two dendrimers, which contain the same luminescent chromophores but differ in dimensionality, for detection of an explosive analyte via PL quenching. Each dendrimer has first generation biphenyl dendrons with 2-ethylhexyloxy surface groups core units. One a bifluorene and hence "planar" structure, whereas second four units tetrahedrally arranged around adamantyl center "three-dimensional" structure. Solution Stern–Volmer measurements have previously been reported to show that...
We have carried out absorption, time-resolved fluorescence, and fluorescence quantum yield measurements of four new soluble anthracene derivatives. They show natural radiative lifetimes in the range 2.5–4.4 ns, which is 5–10 times shorter than those reported for unsubstituted anthracene. The 9,10-bis(phenylethynyl)anthracene (BPEA) derivatives largest transition dipoles, attributed to extended π-conjugation between phenyls through acetylene linkages. Spin-cast films BPEA strong quenching by...
Real time vapour detection efficiency is reliant on analyte diffusion rather than amplified fluorescence quenching processes based exciton diffusion.
A first generation dendrimer comprised of a 9,9,9',9'-tetra-n-hexyl substituted 2,2'-bifluorene core, biphenyl dendrons, and 2-ethylhexyloxy surface groups can rapidly detect high electron affinity, explosive-related analytes such as pnitrotoluene 2,4-dinitrotoluene. Stern-Volmer analysis the in solution showed that quenching could be either collisional or static but not combination two mechanisms. The was found to critically dependent on correcting for absorption analyte at excitation...
We have measured the infrared, Raman and inelastic neutron scattering (INS) spectra of a series oligothiophenes (bithiophene, terthiophene, quarterthiophene, sexithiophene octithiophene) polythiophene, both pristine after doping with iodine. The (i.e. neutral) systems show rapid convergence towards spectrum such that octithiophene are almost indistinguishable from polythiophene. spectra, in combination periodic density functional theory calculations, also provided first complete assignment...
Abstract Polymeric binders such as β‐cyclodextrins (βCDs) are used to bind with other constituents of energetic formulations and prevent accidental ignition. One the advantages βCDs is ability tune their properties by chemical modification. Here, we synthesised nitrated cross‐linked (βNCXCDs) produce new for formulations. The cross‐linking βCD non‐toxic triethylene glycol diglycidyl ether (TEGDGE, X=T) poly(ethylene glycol) ethers (PEGDGE, X=P) yielded soft, water soluble oligomeric...
We find that water morphology within melanin is purely interfacial in nature, even at high contents. This brings into question the proton conduction mechanism with implications or other conductive biomaterials.
Reported herein is a neutron reflectometry (NR) study on hydrated Nafion thin films (∼30 nm) silicon substrate with native oxide. The morphology investigated systematically across the whole relative humidity range using both H2O and D2O vapours to enable comparative study. By utilising this systematic approach two key results have been obtained. first that by leveraging strong positive scattering signal from vapour, complete water adsorption isotherm (Type II) for film produced. Utilising...
We have investigated caesium hydrogen sulfate, CsHSO4, in all three of its ambient pressure phases by total scattering neutron diffraction, inelastic (INS) and Raman spectroscopies periodic density functional theory calculations. Above 140 °C, CsHSO4 undergoes a phase transition to superprotonic conductor that has potential application intermediate temperature fuel cells. Total diffraction data clearly show the existing structures this are unable describe local structure, because they either...