Wednesday, 12 July 2017

Advanced Resource Efficiency Centre (AREC) Showcase in the European Parliament




On 27th June 2017, the AREC team, led by Professor Lenny Koh, showcased its research and impact at the ‘Pathways to Global Policy, Industry and Societal Impact on Resource Efficiency and Sustainability’ event at the European Parliament, Brussels.

The event was hosted by John Procter, MEP for Yorkshire and Humber, through the White Rose Brussels group (https://brussels.whiterose.ac.uk/) and attended by policy makers, industry representatives and academics. The main aims of the event were to present the impact of AREC’s research and develop potential future connections to further extend AREC’s impact reach.


The event included a panel discussion from Professor Lenny Koh, Professor Panos Ketikidis (Vice Principal: Research and Innovation, International Faculty of the University of Sheffield in Thessaloniki, Greece), Jay Sterling Gregg (European Energy Research Alliance, representing “e3s”, Brussels, Belgium), Philippe Micheaux Naudet (Association of Cities and Regions for Sustainable Resource Management – ACR, Brussels, Belgium) and Maria Rincon-Lievana (Policy Officer – Circular Economy Action Plan, DG Environment, Brussels Belgium).

Professor Koh presented the SCEnATi (Supply Chain Environmental Analysis) tool to the group of industry specialists and academics. The SCEnATi tool is used within the FMD group to produce comparative hybrid life cycle assessments of functional materials and devices.

Professor Koh commented “Being resource efficient and sustainable should be embedded as a new norm in every supply chain, every business and every organisation whether these are public, private or third sectors. Policies that support this goal, industry practices that promote such implementation, technologies/tools that enable this achievement, and research and innovation that underpin the delivery of this new norm would lead to positive societal, economic and environmental impact”.


For further information on the SCEnATi tool please contact: Lucy Smith, lsmith17@sheffield.ac.uk

Thursday, 6 July 2017

Full Tilt - Why it Matters in Matter

"Tilting" in perovskites is all about the subtle arrangements of atoms in materials, which is inherently related to the properties of materials, such as capacitors and piezoelectrics. Tilt is also something we can control, by doping a material with another type of atom. By controlling tilt, we can design novel materials.

http://www.nature.com/nphoton/journal/v8/n7/full/nphoton.2014.134.html
I am not a materials scientist by training, but a computational chemist with a background in simulations of water, peptides, and using machine learning. So I don't think of atomic structures are rigid arrangements of atoms, but being dynamic. So I see perovskites not as neat octahedral units of B site atoms surrounded by oxygen atoms (or whatever the X site atom happens to be). In reality these octahedral units are irregular, and fluctuating, especially at ambient conditions and when heated. But if you only consider X-ray diffraction determined crystal structures, you may be led into thinking the opposite.

So what do we mean by "tilt"?

Tilt means that the octahedral units that we have defined, are aligned in a manner that means the octahedral units either do, or do not, superimpose upon their neighbours. This tilt is classically defined by Glazer (using a frustrating description of rotation if you prefer Euler angles!), and from which we get different crystal structure classifications that differ by the manner the octahedral units tilt and overlap.

In the material calcium titanate, all the A site atoms are barium, the B site titanium, and X sites are oxygen. At high temperatures calcium titanate exhibits no tilt. It's cubic. But when we start to dope the material on the A site, with larger or smaller ions, such as barium, we begin to distort the structure. Or if we cool the material down, tilting emerges.



AA3B4X12 perovskite structure showing the octahedral environment of the B cation
http://pubs.rsc.org/en/Content/ArticleHtml/2010/JM/b926757c

Distorting the material has a knock on effect on the ions in the material. The titanium now no longer sits in an isotropic (so a fully symmetric and even) electrostatic field created by the oxygen atoms about it. This means the titanium atoms get shifted. The same happens with the calcium ions too.

It's this combination of distortion that generates a dipole moment - a displacement of electrostatic charge in a particular direction within the crystal structure.

So what is the challenge in materials science?

Exploring how we can dope materials, and manipulate this tilting, in a targeted manner, relies on experiment and theory working in tandem. X-ray diffraction defined structures do not show the oscillations but use structure factors to account for thermal scattering that induces oscillations of the atomic positions. From Transmission Electron Microscopy (TEM) we can generate diffraction patterns which can show this oscillation of structure. And from theory, via simulations of atoms via Molecular Dynamics, we can assess the degree of tilting (not defined by Glazer), and begin to predict TEM diffraction patterns.

The hope then is that a combination of techniques, both experimental and theoretical, can reveal further insight into the complex relationship of atomic structure and materials properties.


 Atomic resolution image of 2D halide perovskite CsPbBr 3 . (a) Structure model of cubic CsPbBr 3 perovskite unit cell. Cs (green) occupies the corner A-site while Pb (gray) occupies the body-center Bsite , and Br (brown) occupies the face-center. Pb−Br 6 octahedron is formed within the Cs cube framework. (b) Structure model of single layer 2D CsPbBr 3 NS. (c) Atomically resolved phase image of a 2D CsPbBr 3 NS obtained by reconstructing 80 low dose-rate AC-HRTEM images via exit-wave reconstruction. The [001] structure projection of a unit cell is overlaid on the image.
http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.6b03331  








Wednesday, 7 June 2017

Functional Materials for a Sustainable Future

Last month, on the 15th of May, the University of Sheffield Functional Materials and Devices group hosted a workshop centred on the topic of "Functional Materials for a Sustainable Future". A diverse number of speakers from out own group, and collaborators, and industrial partners, gave insightful and exciting talks on how a range of materials can be designed and fabricated, for use in a wide range of applications.

Presentations ranged from magnetic materials for cooling, solar power materials, and the use of computational simulations to model novel materials. The workshop was also an opportunity for the FMD group to demonstrate the value of KTP (Knowledge Transfer Partnerships) whereby researchers can pursue underpinning research to enable novel materials discovery and applications.

Guests included representatives from QinetiQ, Johnson Matthey, CeramTec, Rolls-Royce, and more (a full list can be found on the event page).

























Functional materials in Japan

The assembled attendees
Between the 29th and 31st of May, the 8th International Conference on Electroceramics (ICE) was held at Nagoya University in Japan.

Topics covered at the conference encompassed most of the oxide functionalities, including piezoelectrics, thermoelectrics and ferroelectrics. Plenary lectures included Prof John Kilner (Imperial), Prof Harry Tuller (MIT), and Dr Nava Setter (EPFL).

Attendees included academics, students and industry representatives, which enabled some interesting discussions about the future directions of functional materials.  

Becky receiving her prize
Becky attended as a speaker, talking about her work on control of morphology in barium titanate, for which she won a Young Presentation Prize.

There was also a moving memorial symposium for the late Prof Eric Cross (PSU) a pioneer in the ferroelectrics field, who passed away at the end of 2016, with contributions from former students and colleagues.

Wednesday, 10 May 2017

Invited lecture at Manchester University on perovskite solar cells


On May 3rd 2017, Dr Giorgio Schileo was invited to give a lecture on the state-of-the-art and industrial applications of perovskite solar cells to Renewable Energy MSc students at the University of Manchester.

The talk covered the physical chemistry aspects of perovskite solar cells, including insights on the challenges that a new technology must face to make the transition from academic novelty to useful product that generates a profit. Perovskite solar cells are a good example of this process, as they generated an enormous amount of interest in the academic community and attracted considerable investments worldwide, even though critical issues (stability, toxicity of Pb, etc.) still have to be addressed.

Dr Schileo also presented the KTP scheme to the students as a possible route to secure a job in the industry while gaining some additional skills, and also different aspects such as market shares, overall cost considerations, and scale-up issues.


Monday, 10 April 2017

1st Annual ICON Conference, Athens

On April 7th 2017, Becky was an invited speaker at the International Consortium of Nanotechnology's (ICON) 1st Annual Conference. This Consortium provides funding for a global network of PhD students working in a wide variety of nanotechnology fields such as graphene and perovskite solar cells. ICON is an initiative funded by the Lloyd's Register Foundation (LRF), who also supports Becky's fellowship. The LRF are a charity committed to improving the safety standards in engineering across the globe, and to promote scientific education, with ICON being one of their flagship schemes.    




The conference was a mix of fascinating talks about ICON, the LRF, and presentations from the PhD students themselves each of whom had three minutes to explain their work. Each speaker rose to the challenge and it was a great introduction to their work and to the later poster session. 

Becky's talk was about where a career in nanoscience could lead, by drawing on her experiences as both a PhD and PDRA. Following on from the experiences of an LRF-funded PhD student coming to the end of her work, Becky gave a brief introduction to her work and a few hints for the assembled PhD students on getting the most out of their PhDs.

The conference was held in central Athens, Greece, and provided the delegates with the opportunity to explore the wonderful historical sites in the city, including the fantastic conference dinner which was held at the Acropolis Museum, with views of Acropolis Hill and the Parthenon

Friday, 7 April 2017

From Bits to Batteries - Cafe Scientifique Post-Mortem

On Monday, April 3rd, FMD group member, Dr Chris Handley, gave his talk, "From Bits to Batteries", to a public audience thanks to the local Café Scientifique organisation. Café Scientifique is place for academics and researchers to present their work to a public audience, consisting largely of non-experts. Outreach opportunities such as these are an ideal way to demonstrate the value of academic research, and the value of investment into research.


Douglas Bell, who helps organise the Sheffield Café Scientifique events was able to attend,


"Christopher explained the chemistry and the computation approaches clearly. He displayed both in-depth knowledge and enormous enthusiasm for the topics. Visuals were rich in useful diagrams and animations. He handled questions sensitively and helpfully.

The talk was pitched just right for an audience with limited science background. It was well received and fitted well within the programme of Café Scientifique."

Chris' talk demonstrated the importance of computational simulations as a underpinning research tool for materials design and discovery, and generated some excellent discussion, with audience members eager to further understand the future implications of machine learning in the field, and further examples of how simulation and experiment works in tandem within the FMD group.

In the future we hope to present more of our work at these public gatherings, and perhaps have PhD students give shorter presentations as a group.