Darren graham

Congratulations to Dr Darren Graham who was nics?’ recently awarded the very prestigious EPSRC Career Acceleration Fellowship, which he will hold in the Darren will be col- PSI for the next five years. laborating with Nigel Scrutton and Steve The fellowship entitled, ‘Terahertz electron para- Rigby (MIB), David magnetic resonance: a window on biological exploi- Collison and Eric tation of quantum mechanics’, will focus on con- McInnes (EPSRC EPR structing a novel electron paramagnetic resonance facility), Hiroyuki (EPR) spectrometer operating in the terahertz spec- Nojiri (Tohoku Uni- tral range. By utilising the sub-picoseconds capabili- versity), as well as ties of ultrafast laser spectroscopy, this new instru- instrument manufac- ment will enable Darren to address a fundamental turers, Spectra- question in enzyme catalysis, ‘Have biological cata- Physics Lasers and

lysts (enzymes) evolved to exploit quantum mecha- Bruker. Dr Darren Graham

Newsletter sUMMER / autumn 2011

This newsletter consists of a combination of articles, highlighting both recent grant successes and those of a personal nature. Items for future newsletters and/or the PSI website should be sent to [email protected].

CONTROLLED SYNTHESIS OF TUNED BANDGAP NANODIMENSIONAL ALLOYS

Research by members of the PSI aimed at optimizing composition. An important task was to prove that the light-harvesting properties of chalcogenide quan- the particles have a uniform composition. This was tum dots has been published in Journal of the American achieved using energy-filtered transmission electron Chemical Society, widely regarded as the most prestig- microscopy in the Manchester Materials Science ious journal in Chemistry. Centre and by PSI members using X-ray photoelec- tron spectroscopy at the SuperESCA beamline at the The work by Prof Paul O’Brien, Dr Mohammad ELETTRA synchrotron in Trieste. PSI members also Afzaal, Dr Javeed Akhtar, Dr David Binks, contributed to demonstrating the crucial direct cor- Prof Wendy Flavell, Dr Darren Graham and relation between composition and band gap. Dr Samantha Hardman was carried out in col- laboration with partners in the Manchester Materials Published in Journal of the American Chemical Soci- Science Centre and international collaborators in ety, 133, 5602 (2011) - see the following link:

Italy, Poland and Saudi Arabia. http://pubs.acs.org/doi/full/10.1021/ja200750s Small clusters of semiconducting material or ‘quantum dots’ offer great potential as the light- harvesting elements in next generation solar cells— in particular because under certain conditions it is possible to generate more than one set of current NEWSLETTER The science institute The photon carriers for every photon absorbed—a phenomenon known as ‘multiple exciton generation’ or MEG. However, it can prove difficult to synthesise dots with uniform and reproducible composition. Prof O’Brien and his group have been able to find a way

to produce truly alloyed PbSxSe1-x nanoparticles of uniform composition. As the band gap of the mate- PbSxSe1-x ’quantum dots’, imaged using energy-filtered transmission electron microscopy. The bright colours show rial varies with composition, this presents the tanta- regions with high selenium content. Each quantum dot is lizing prospect of being able to tune the energy of the around 5 nanometres across—about 1/100,000th of a light absorbed by the dot by simply adjusting the human hair. Credit: Manchester Materials Science Centre, School of Materials, The . Promotions

Congratulations to Matthew Halsall and Krikor Ozanyan of the School of Electrical and Electronic Engineering, who have been promoted to the position of chair as of 1st August 2011.

Congratulations are also due to Dr Thomas Waigh on his promotion to the position of Senior Lecturer in the School of Physics and Astronomy.

Matthew P Halsall Krikor B Ozanyan Thomas A Waigh Professor of Photonics Professor of Photonic Sensors and Systems Senior Lecturer in Biological Physics

Philip dawson CINZIA CASIRAGHI

Professor Phil Dawson has been awarded an EPSRC grant for £497,000, for the Dr Cinzia study of semi-polar and non-polar nitride Casiraghi and based structures for opto-electronic device her collaborators, applications. Profs Novoselov and O’Brien, These new types of nitride quantum well have been structures could well lead to the develop- awarded a Royal ment of LEDs capable of emitting linearly Society ‘seed polarised light as well as the elimination of Dr Cinzia Casiraghi corn’ grant for the effects of the internal electric fields that £15K to study "Synthesis and characterization are so problematic in conventional polar of molybdenum and tungsten dichalcogenide quantum well structures. analogues of graphene".

Inorganic photophysics and photochemistry: DD13—call for abstracts—DEADLINE 9TH OCTOBER 2011 http://mxm.mxmfb.com/rsps/ct/c/1127/r/20807/l/465097 This is a call for abstracts for the conference and biology — but all with a shared interest Speakers include the following: on Inorganic Photophysics and Photochemis- in the use of light. Whilst the main focus of try - Fundamentals and Applications : Dal- the meeting will be on inorganic com- • Prof Majed Chergui, Ecole Polytechnique ton Discussion 13 will take place from 10- pounds and materials the meeting will be Fédérale de Lausanne, Switzerland 12 September 2012 at the University of broadly-based to reflect the interdiscipli- • Prof Luisa De Cola, Westfälische Wil- Sheffield, UK nary nature of the field, and contributions helms-Universität Münster, Germany from all photophysics-based disciplines will The call for abstracts deadline is 9th be considered. • Prof Richard Eisenberg, University of October 2011. Abstracts may be submitted Rochester, USA via the above link. As the efficient use of light as a renewable energy source is becoming paramount this • Prof Peter Ford, University of California, The fields of photophysics and photochemis- Discussion will focus on the following USA try of metal complexes, and their associated themes: spectroscopic methodology, have never • Prof Chantal Daniel, Université Stras- been more topical. • Solar energy bourg, France

Inorganic Photophysics and Chemistry - • Energy and electron transfer • Prof Leif Hammarström, Uppsala Univer- Fundamentals and Applications: DD13 aims sitet, Sweden to bring together researchers from a wide • Applications of strongly emissive com- range of disciplines — from theory and ul- plexes • Prof Craig Hill, Emory University, USA trafast spectroscopy to medicinal chemistry • Bond breaking and isomerisation • Prof David Parker, Durham University Qinetiq developments

Driven by the need for all weather flying, The PSI has recently received a 35GHz has come to the University for use in educa- remote sensing environmental monitoring quasi-optical security screening portal tion. It generates good quality images and and security screening of personnel, milli- (photo below), which uses mechanical scan- could be used by students in image process- metre-wave imaging technology has been ning, a focusing mirror, a 64-receiver ele- ing and sensor engineering projects. developed by QinetiQ. They are essentially ment focal plane array and an illumination video cameras working in the microwave chamber to generate video rate imagery of The system represents several years of and millimetre wave band and exploit the persons. In maturity it constitutes a Tech- QinetiQ internally funded development; atmospheric properties that over path nology Readiness Level (TRL) 6 system and there were six precursors to this system lengths of hundreds of meters, fog, cloud, was used to demonstrate the capabilities of which were trialled and sold to customers haze and dust storms are largely transparent, millimetre waves for security screening. Six for evaluation. The system now in the Uni- but over much longer paths they provide in- years ago it represented the state-of-the-art versity represents the final and most sophis- formation about the weather and atmos- in millimetre wave security screening tech- ticated system of the series. The build cost pheric constituents. Security screening of nology but was deemed by business leaders of a single system was ~£400K and when personnel is enabled by the semi-transparent as being too large for deployment as an air- the system is assembled it is 2m wide × 2m nature of clothing and packaging materials. port security screening system; hence, it high × 4m long.

The 35GHz quasi-optical security screening portal showing the illumination chamber on the left hand side and the back of the imager on the right hand side. Photo credit: QuinetiQ Ltd.

Dr Neil Salmon, a aperture synthesis imager uses a 32- integrated into existing building infrastruc- QinetiQ Fellow, receiver element aperture array, a 300MHz tures for security screening, into aircraft holds a Royal Soci- bandwidth digital cross-correlator and algo- skins for all-weather flying. ety Industry Fel- rithms running in a standard PC, to gener- lowship to work in ate video imagery in the near and far-field. This system generated its first images in the PSI, and has It represents the current state-of-the-art in April of this year, to the delight of Technol- been responsible for next generation millimetre-wave imagers ogy Strategy Board and European Space developing a and a possible future for imaging in this Agency sponsors. The system is unique and Dr Neil Salmon 22GHz millimetre band, as it has the potential to deliver bet- is generating exciting new data, which is wave imaging sys- ter quality images (namely three- currently being evaluated so that a next tem from a technique initially pioneered for dimensional in the near-field) and be made generation TRL 5 system can be designed radio astronomy into one with commercial much more compact. As the technology and built for existing and new customers in and research applications in other areas. could ultimately be integrated into a 2cm the security and aerospace industries. thick printed circuit substrate, it could be The small 22GHz TRL 4 proof-of-principle Continued on page 4 QINETIQ developments continued

Other developments achieved by the Royal term weather forecasting (now-casting). Society Fellowship funded QinetiQ Fellow, Only an aperture synthesis imager can meet Dr Neil Salmon, include 94GHz and the launch weight and volume payload re- 183GHz aperture synthesis imagers (photos quirements; a quasi-optical imager would overleaf). These have been developed as exceed the payload limits. TRL 4 laboratory demonstrators for the European Space Agency (ESA) Terahertz The Michelson interferometer Fourier trans- Camera initiative. They are dual use test form spectrometer, located in the PSI, is ca- beds for security screening imagers and the pable of making very precise measurements ESA Geostationary Atmospheric Sounder of the refractive index and extinction coeffi- (GAS) programme. Used for security cients of materials with sub-GHz frequency screening, the system generates small im- resolution over the 80-1200GHz spectral ages with a spatial resolution of 2cm at a range. The system has been used extensively range of 2m. by QinetiQ in the characterisation of materi- als used in its millimetre wave imagers and The GAS programme has the 10-year time- for understanding the signatures of threats scale goal of launching an Earth observation and the properties of clothing and packaging satellite into orbit to monitor the environ- materials for security screening. The system ment. The imager of this sensor needs to is on long-term loan to the University of have an aperture size of 7m to achieve the The 94GHz, 10-channel aperture synthesis Manchester to support research and technol- required 30km diffraction limited spatial imager (above) and the 183GHz, 4 channel aper- ogy development projects in the millimetre ture synthesis imager (below), as demonstrators resolution on the Earth’s surface for short for next generation earth observation and secu- and sub-millimetre wave bands. rity screening technology.

New Device Developed to Measure Opaque Material Velocity Profiles

Dr Matthew Harvey and Dr Tom phenomena have been measured such as wall Waigh of the Biological Physics group, slip and shear banding. The apparatus uses School of Physics and Astronomy, have built optical fibres. It is built around a Michelson a new device that allows the velocity profiles interferometer and functions at infra red of opaque materials to be measured as they wavelengths. are sheared. They have used it to study a range of soft matter systems under flow Reference: M Harvey, T A Waigh, ‘Optical including colloids (polystyrene spheres in coherence tomography velocimetry in con- water), polyelectrolytes, margarine and trolled shear flow’, Physical Review E, 2011, 83, 031502. plant cell suspensions (tomato ketchup). Two dimensional velocity profile of colloidal Unusual fluid mechanics/viscoelastic spheres measured across the gap of a plate-plate rheometer sheared at a constant rate.

Cover article

Dr David Binks has written a 'perspective' discusses the controversy that has surrounded article by invitation of the editors of 'the Jour- MEG in recent years and the improved un- nal of Physical Chemistry Chemical Physics, enti- derstanding of experimental data that has tled ‘Multiple exciton generation in nanocrys- emerged recently, which has allowed seem- tal quantum dots – controversy, current ingly contradictory results to be reconciled. status and future prospects’. The article also examines the current state-of -the-art, the potential impact on solar cell Multiple Exciton Generation (MEG) is an efficiency and proposes a quantum dot struc- effect in nanocrystals by which a single ab- ture designed to optimise MEG efficiency. sorbed photon can produce multiple charges, and has the potential to significantly improve the efficiency of solar cells. The article http://pubs.rsc.org/en/journals/journalissues/cp EPS SCHOLARSHIP talk prize

In competition At the Centre for Doctoral Training Nano- stable under am- with other appli- conference Conference 2011, held on 5-8 bient conditions. cants, Miss June, Mr Thanasis Georgiou was Thanasis has Huafeng Yang awarded third prize for his talk entitled, shown it is possi- has been awarded a “Graphene bubble as adaptive focus lens”. ble to control the Faculty Scholar- Supervised by Dr Cinzia Casiraghi and Prof curvature of a ship, which will Kostya Novoselov, Thanasis is in his first bubble and pay her fees and year of PhD study and has shown that gra- change its shape

maintenance for phene bubbles are good candidates for mak- by applying a gate Huafeng Yang three years. ing adaptive-focus lenses. voltage. This behaviour enables Miss Yang will commence PhD study in Robust, cheap and optically transparent, graphene to be Thanasis Georgiou September under the supervision of Dr Cin- graphene is a useful material for use in op- used in optical zia Casiraghi to study a project entitled, tics. However, small bubbles are found elements, for example, as the basis for an “New composite materials based on gra- when large area graphene flakes are depos- adaptive focus lens. phene for solar cells and ”. ited on a substrate. These bubbles are highly

NEW X-RAY IMAGING BEAM line http://www.sciencedirect.com/science/article/pii/S1359029411000938 A new Coherent X-ray imaging beam line the emerging techniques has been published.1

(l13) has been commissioned at the Diamond Objective lens Synchrotron Centre, opening up a range of Phase ring new opportunities for imaging condensed Sample

matter with 10-50nm resolution for the UK Science Community. Detector The imaging techniques do not need invasive Condenser lens Dr Tom Waigh sample preparation methods, as are required for transmission electron microscopy — microtoming of specimens X-ray and neutron imaging of nanoparticles is not required. Furthermore, fluorescent staining is not required, as with super-resolution microscopies at visible optical wavelengths. In Reference1: X-ray and neutron imaging with colloids, T A Waigh, C Rau, addition, thick opaque samples can be investigated. A new review of Current Opinion in Colloids and Interface Science, 2011, see above link.

Big ideas for the DAVID WATTS future Professor David party of the Institute of Materials and the Published by Research Councils UK, “Big Watts of the Institute of Engineering in Medicine. The Ideas for the Future,” June 2011, includes School of Dentistry UKSB is the demographic Society for the an article on the microsphere optical nano- was awarded the whole biomaterials community. scope developed by Prof Lin Li, Dr 2011 President’s Zengbo Wang et al. on page 34, entitled, Prize for leadership In Berlin earlier that week, on 27 June, “More Powerful Microscopes.” in Biomaterials David attended a lecture on science policy research at the UK by Federal Chancellor, Dr Angela Merkel. Society for Bioma- Attendance by invitation only was organized by the Alexander von Humboldt Founda- Prof David Watts terials annual con- ference held at the tion. University of Greenwich, 30 June to 1 July Every year the Foundation enable more than 2011. David gave a keynote lecture entitled, 2,000 researchers from all over the world to “Are you enjoying biomaterials research”. spend time researching in Germany. The The UK Society of Biomaterials (UKSB) was Foundation maintains a network of well set up to serve a diverse, interdisciplinary over 25,000 Humboldtians from all disci- biomaterials research community. This was plines in more than 130 countries world-

in response to the findings of a joint working wide, including 44 Nobel Prize winners. http://www.rcuk.ac.uk/documents/publications/ PUTTING SUNSHINE IN THE TANK— USING NANOTECHNOLOGY TO MAKE SOLAR FUEL http://royalsociety.org/summer-science/2011/solar-nanotech/ Scientists from the PSI are working on how night?’ If we can store the energy harnessed to use the energy of the Sun to make fuels, from the sun during the day then we will which could help to solve the world’s esca- have supplies ready to use when the sun is lating energy crisis and presented their re- not shining. This is a first step in taking the search at the Royal Society’s annual Summer vast power of the sun and using it to pro- Science Exhibition held 5-10 July 2011. vide the world’s fuel needs.”

Working with the Universities of East An- The Royal Society Summer Science Exhibi- glia, York and Nottingham and using tion showcased cutting edge research in nanotechnology 100,000 times smaller than Making solar fuel: light-driven generation of hy- science and engineering from across the UK the thickness of a human hair, the research- drogen at an electrode using a molybdenum and is held annually at the Royal Society, ers are working to harness the vast energy of catalyst. the UK’s national academy of science. This Photo credit: Energy Materials Laboratory, Univer- the Sun to produce clean fuel. sity of East Anglia year, 21 exhibits were selected from 97 applications. Members of the consortium at UEA have al- absorb sunlight. ready found a way to produce hydrogen At the exhibition, Professor Flavell and her from water. A revolutionary future use of When sunlight is absorbed, carriers of elec- team displayed an interactive world map this technology could be to make the fuel for tric current are created. Together with cata- which showed children and other visitors hydrogen-powered cars, rather than making lyst molecules grafted to the surfaces of the just how much energy the Sun provides. it from fossil fuel. Now the scientists are dots, these create the new fuel – for exam- aiming to use the same technology to create ple hydrogen can be produced from water. There was also a chance to see the quantum alternatives for other fuels and feedstock dots at work, and show simply by changing Professor Flavell said: “Our sun provides far chemicals, including turning methane into the size of the dots, how the colour of light more energy than we will ever need, but we liquid methanol and carbon dioxide into car- they absorb or give out can be changed. A use it really inefficiently. To make better bon monoxide. solar cell that produces hydrogen directly use of the fantastic resource we have in our from the electricity generated was on dis- The sun’s potential is vast – just one hour of Sun, we need to find out how to create solar play and a chance to race solar-powered sunlight is equivalent to the amount of en- fuel that can be stored, shipped to where it and hydrogen-powered model racing cars. ergy used over the world in an entire year – is needed and used on demand. Most hydro- yet no one has yet tapped into its immense gen has so far been obtained from fossil The team working on the exhibit was 25- power to make fuels directly. fuels, which will not last forever, so it is strong, from four participating universities. important to get energy from renewable The PSI team included Wendy Flavell, Professor Wendy Flavell, from the sources. David Binks, Andrew Thomas, Dar- School of Physics and Astronomy, and her ren Graham, Samantha Hardman, colleagues are working to create a solar- One of the key questions is: ‘what do we do Karen Syres, Patrick Lunt, David nano-device using ‘quantum dots’ – tiny when the sun goes down, what happens at Cant, Jon Treacy and Icell Mah- clusters of semiconducting material which moud.

Helen gleeson

At the recent International Conference on The conference covered a wide variety of Frontiers of Polymers and Advanced Mate- topics in materials science and Helen gave a rials, held in Pretoria (May 2011), Profes- Plenary Lecture on Laser Tweezing in Liq- sor Helen Gleeson was presented with uid Crystals. Attending the conference also an award in Recognition of her Achieve- gave the opportunity to follow up on a ments in Scientific Endeavors. Helen was Royal Society funded visit to the Laser Insti- one of two women who received the tute in Pretoria, made with Mark Dickinson award, which was presented at the confer- and David Binks in September 2010. ence dinner, having had her face painted in traditional Zulu style! Prof Heleln Gleeson

Please send any items you have either for The Photon Science Institute website or the next newsletter to [email protected]