Centre for Sustainable Chemical Technologies

Scientists and engineers working together for a sustainable future

Tagged: Oliver Weber

Developing the Next Generation of Solar Cells at Oxford PV

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📥  Case Studies, Comment, Internships & visits

Since January I’ve been working with scientists and engineers at Oxford Photovoltaics, a start-up company spun out from Oxford University research that aims to scale up and commercialise perovskite solar cells (so named for the crystal structure of the absorber material).

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Perovskite cells have obtained similar efficiencies to established solar cell technologies like silicon, but are thinner, cheaper and easier to make. They can also be engineered to absorb a different part of the visible solar spectrum than silicon and so be integrated straight on top of silicon cells to make a tandem device that is more efficient than either component on its own.

Instability has been a major problem to solve for perovskite cells, but the research community has made rapid progress on designing more stable devices since they were first reported just a few years ago.

How did I identify this placement?

Basically by speaking to people! I met engineers from Oxford PV at a conference in Swansea and asked if they’d consider hosting a placement student. An interview and a few logistical matters later it was somehow already time to begin.

What were the key differences to working in an academic setting?

The pressures definitely feel different to academia. At University you want to explore research questions in depth and preferably be the first person to publish and tell the world about your science, while in industry everything is kept under wraps. You have to focus on quickly delivering the commercial aspects of the research, even if it means leaving interesting tangential questions unanswered, since the commercial competition is fierce.

What would I recommend for students thinking about an internship?

Absolutely go for one! Be careful that both you and the host organisation know what to expect, bring energy and enthusiasm to the role and it’s a real chance to learn a lot in a different environment, potentially outside your comfort zone. Three months is not a lot of time to execute a project in a new setting, so I had to quickly get up to speed with procedures and equipment. The result is that I’ve had a fantastic time, learnt a huge amount both scientifically and about how things are done in a start-up company and met many people working on making a promising new renewable energy technology into a commercial reality.


Oli is studying towards his PhD on 'Optimizing energy harvesting processes in metal halide photovoltaics' with Professor Mark Weller and Professor Chris Bowen.

 

Boston Materials Research Society Conference

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📥  Seminars & Conferences

Oli Weber (Cohort '13) and Dan Davies (Cohort '14) recently attended the Boston MRS Fall Meeting 2016. This post was jointly written about their experience.


The CSCT was well represented at the Boston MRS Fall Meeting 2016, with myself, Dan Davies, Jemma Rowlandson (previously Cohort ’13, now University of Bristol) and alumnus Dr Adam Jackson (Cohort ’11, now UCL) in attendance. A major international conference can be an overwhelming experience, especially when it spans, conceptually, the whole of materials science and physically, an entire conference venue and the hotel next door. Much of the week was spent dashing between seminar rooms, trying simultaneously to catch the best talks while working off the effects of overlarge food portion sizes.

I embodied an academic stereotype by writing my presentation on the flight on the way to the conference, having being told at the last minute that my poster abstract could be swapped for a talk. I gave my talk on the first day of the conference in symposium ES3: Perovskite Solar Cell Research from Material Properties to Photovoltaic Function. I spent a fair amount of time in the perovskite session, hearing numerous exciting results, though many of my personal conference highlights came from wandering into seminar rooms with tangential or non-existent links to my own research. I heard Shreyas Shah from Bell Labs speak on interfacing nanomaterials with neural stem cells for neural regeneration, by combining visible light-responsive ion channels and upconversion nanoparticles to transform infrared light transmitted through biological tissue into blue luminescence to achieve optogenetic control of neuronal activity.

Oli takes in the sights

Oli takes in the sights

There were many other great talks, including Yi Cui from Stanford, on thin film silicon photovoltaics, Dan Nocera from Harvard, on complete artificial photosynthetic systems and Yuval Goren on the conservation of clay cuneiform tablets in the Negev desert, which are the oldest written records and provide the only external account of the Trojan war.

Meanwhile, Dan presented a poster in the TC2 symposium on high throughput screening of inorganic materials. The poster sessions at the MRS meetings are always very well attended and quite intense – it can feel like giving a two-hour oral presentation! The work went down pretty well though and it was a great opportunity to discuss it with so many researchers with such a broad variety of interests and backgrounds.

Oli, Jemma and Dr Valeska Ting get a photo during the meeting.

Oli, Jemma and Dr Valeska Ting get a photo during the meeting.

Other than that, Dan spent most of his time in the TC1 and TC2 symposia on computational materials chemistry and materials discovery guided by computation. The work presented in TC2 by curators of the Materials Project, Gerbrand Ceder and Kristin Persson, was particularly interesting as a demonstration of the high-throughput calculations that are now possible with modern supercomputers. On the flip side, the TC1 symposium had some really interesting sessions on machine learning, where it was shown how data-mining and statistical analysis techniques are now being used to predict new materials, thereby avoiding costly quantum mechanical calculations altogether. Anubhav Jain from Lawrence Berkeley National Lab presented some new codes he had developed in order to aid materials scientists who are interested in applying data-mining techniques.

The conference also had some excellent sessions on the ‘Broader Impact’ of materials research. For example, the symposium BI1: Today’s Teaching and Learning in Materials Science – Challenges and Advances, featured some very impressive educational studies on the best approaches for teaching undergraduates and graduates materials science topics. These sessions were ideal for picking up transferable knowledge and tips that could be applied in teaching roles as well as in public engagement activities.

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Oli is studying towards his PhD on 'Optimizing energy harvesting processes in metal halide photovoltaics' with Professor Mark Weller and Professor Chris Bowen.

Dan is currently working on his PhD project: 'Interface engineering for indium-free transparent electronics' with Professor Aron Walsh, Dr Duncan Allsopp and Dr Ben Morgan.

 

Hybrid Organic Photovoltaics Conference, Swansea, 2016

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📥  Comment, Seminars & Conferences

This post was contributed by Oli Weber following his attendance at the Hybrid Organic Photovoltaics Conference (28 June - 1 July 2016).


Recently Dom Ferdani (cohort ’14) and I took a trip to the south coast of Wales to attend the 2016 Hybrid Organic Photovoltaics Conference (HOPV 16). The venue was Swansea’s brand new Bay Campus, a huge new development of university buildings sited right by the beach of Swansea Bay. On the first conference day we were met by serious weather blowing in from the sea, leaving delegates from warmer climes wondering what manner of people could be mad enough to inhabit such a cold, damp land. Bay Campus is also the new home to SPECIFIC, the conference hosts, whose mandate is to span the space between academia and industry to develop materials that turn buildings into power stations using functional coatings. Building integrated photovoltaics (BIPVs) are one of the families of technologies developed at SPECIFIC. These rely on thin, lightweight, flexible designs and manufacturing methods, such as printing, that scale up well. Organic semiconductors, dye sensitised solar cells, CIGS and CZTS are all under research and development, however the technology that has come to dominate the research focus for this conference is hybrid perovskite solar cells.

Dom and Oli in Swansea

Dom and Oli in Swansea

Hybrid perovskites combine the properties of some of the highest quality known semiconductors, such as GaAs, with the solution processability of organic materials. This means that the solar cells could be manufactured at low cost, while still displaying the high efficiency of the best inorganic thin films. Unfortunately the hybrid perovskites are not very chemically stable and are easily attacked and degraded by water. Some of the typical device layers used in perovskite cells may also be contributing to the degradation, so it is still difficult to assess whether these materials will be intrinsically stable, over a 25 year lifetime, if they are properly encapsulated as protection from the environment. It was encouraging to see stability data discussed during the research presentations, particularly in the talk by Professor Mike McGehee of Stanford, whose group is developing semi-transparent perovskite top cells to include directly above standard silicon modules to make a more efficient tandem stack.

Other highlights for me personally were the advanced printing techniques run by SPECIFIC researchers on the day before the conference commenced, when we learnt about the pitfalls that await between laboratory scale work and development of cells suitable for bulk manufacturing at large scale. Professor Laura Herz of Oxford Physics gave an excellent presentation on the amount that can be learnt about charge carrier dynamics within perovskite semiconductors using terahertz photoconductivity and photoluminescence measurements. From the University of Bath, Professor Aron Walsh and Dr Petra Cameron both presented recent research results.

Overshadowing the whole conference was the spectre of Brexit. Many people had learnt the referendum result just before setting out to Swansea. Swansea is one of the areas of the UK that voted to leave despite receiving extensive regeneration funding from the EU; SPECIFIC itself is part EU funded. The research groups present were drawn from diverse international backgrounds and many of the research collaborations, already in progress or spawned during the conference, span the EU and further afield. One thing for certain is that the scientific community will continue to find ways to maintain their international networks and friendships whatever the political landscape. From my point of view (and that of many I spoke to) it’s frankly embarrassing that the referendum campaign was fought, won and lost on the basis of fear, lies and bigotry, drowning out all vestiges of the rational debate scientists thrive on. For a country priding itself on freedom and enterprise, we cannot claim to have a healthy political or media culture.

Sitting on the terrace of the conference hall, the beach ahead of me, it is impossible to ignore the juxtaposition of frenetic scientific activity behind me, as brilliant people from every part of the world work to develop clean energy sources for the future, with the EU and Welsh flags taut in the sea breeze just in front and, visible further along the coast, Port Talbot steelworks, in the news as 4,000 people wait on tenterhooks to hear if their livelihoods will disappear. Swansea is an area already hard hit by disappearing traditional industries, on the sharp end of globalised trade. The referendum vote has already delayed and could wreck buyout bids to retain the steelworks, with 69% of Welsh steel exported to the EU. Projects like SPECIFIC serve a dual purpose, for research and as attempts to sow new seeds of industrial activity for clean technologies for the twenty first century. If and when the UK regains political leadership, it will be up to UK government to prove it can support these activities as well as the EU did, or risk watching top researchers and research, as on display at HOPV, move elsewhere.


Oli is Cohort '13 of the CSCT, studying towards his PhD on "Optimizing energy harvesting processes in metal halide photovoltaics" with Professor Mark Weller and Professor Chris Bowen.

 

Durham Rietveld Refinement & Powder Diffraction School 2016

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📥  Internships & visits

This post was contributed by Oli Weber


This week I left the relatively safe confines of Bath behind to traverse the country diagonally up to Durham, a well-travelled route since Medieval times, when pilgrims would visit the shrine of St. Cuthbert hoping to find cures for gout, leprosy or demonic possession. My purpose was to attend the biennial powder diffraction school held at the University of Durham, along with scientists and engineers from all over the world.

Crystallography, the study of atomic structure using diffracted waves of X-rays, neutrons or electrons, underpins a vast amount of science and technology, including my own research into solar cell materials. Collection and analysis of the data can be far from straightforward, and we took part in a series of lectures, tutorials and computer workshops designed to help us grapple with problems from the routine to the diabolical.

The sights of Durham - somewhere in the fog there’s a cathedral.

The sights of Durham - somewhere in the fog there’s a cathedral.

The opportunity to travel to absorb new ideas and meet new people with shared research interests is without doubt one of the best parts of life in the CSCT. The evenings after the formal course were packed with social events centred on Grey College bar, or a treasure hunt around the city with crystallographically themed cryptic clues.

All in all, this was an excellent course for reinforcing theory and technical knowledge in structure refinement techniques. I’d like to thank the course organisers, particularly Professor John and Dr Ivana Evans, as well as the CSCT for funding my participation.


Oli is in his third year of the CSCT, studying towards his PhD on "Optimizing energy harvesting processes in metal halide photovoltaics" with Professor Mark Weller and Professor Chris Bowen.

 

 

 

Conference report: RSC Solid State Group Easter Meeting 2014

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📥  Seminars & Conferences

The RSC Solid State Group Easter Meeting was organised by Professor Aron Walsh (University of Bath) and Dr David Scanlon (UCL) and was held at the Kavli Royal Society International Centre in Chicheley between 14-16 April 2014. This post was contributed by 2nd-year research student Jessica Bristow.

The meeting was attended by both staff and students researching solid-state materials for energy generation, storage and conversion. Over three days multiple topics were addressed including: catalysis, battery technology, photovoltaics, fuel cells and photocatalysis.

One particular personal highlight was the talk by Professor Richard Catlow of UCL who gave a general overview of progress made in the area of solid-state modelling and catalysis. He highlighted the importance of not just trusting published data and that all available computational techniques should be used in cooperatively finding a solution, rather than trusting an individual method.

The meeting also included three excellent talks from Steven Wood, Adam Jackson and Mako Ng, studying in the DTC for Sustainable Chemical Technologies.

Steven spoke about potential materials for sodium ion batteries as an alternative to the current lithium ion batteries. Steven employs molecular mechanics as a means to theoretically predict material properties for a given application.

Adam and Mako both spoke about CZTS, a material composed of copper, zinc, tin and sulphur. CZTS is a popular future photovoltaic material with the potential to be a more sustainable choice for devices to capture the suns energy and convert this to electricity. Adam gave an overview of calculations he has conducted on CZTS, while Mako presented his experimental work synthesising large crystals of the material.

RSC SSG Easter Meeting 2014
  • Steven Wood is supervised by Professor Saiful Islam (Chemistry) and co-supervised by Dr Tim Mays (Chemical Engineering);
  • Adam Jackson is supervised by Professor Aron Walsh (Chemistry) and co-supervised by Professor Laurie Peter (Chemistry) and Dr Darrell Patterson (Chemical Engineering);
  • Mako Ng is supervised by Professor Mark Weller and co-supervised by Professor Aron Walsh and Dr Philip Shields (Electrical & Electronic Engineering);
  • Jessica Bristow is supervised by Professor Aron Walsh and co-supervised by Dr Valeska Ting (Chemical Engineering).