Imperial Materials

Divija Sachdeva and Roman Ogorodnov, two undergraduate students from the Department of Materials, have recently finished their learning placement at AlixLabs in Sweden. Throughout their placement, they conducted an investigation into semiconductors fabrication.

Divija and Roman sought out their placements through networking and direct applications on LinkedIn. Their placements were independently funded and conducted during the Easter break.

In this blog post, they share more about their placement, what they learned and how this will positively impact their future studies.

Being Materials Science students, every day, we learn more about the pillars of its foundation and the technologies in the current modern world that are still in the developing phase. We start this degree with a rough (engineering) drawing of what our future aspirations are, which soon become the drive to be a part of the revolution for new sustainable and revolutionary materials. Roman and I wanted to learn more about the fabrication of semiconductors and advanced transistors because of our heavy interest in exploring how the new techniques for etching are being developed and being a part of it. 

Our placement with AlixLabs

In April 2023, we had the opportunity to interact with the Researchers at AlixLabs in Lund, Sweden, during a three-week learning placement under their supervision. On our first day, we sat down with Dr Dmitry Suyatin, the Co-founder of AlixLabs, who explained to us their vision, which was to develop a specific Atomic Layer Etching (ALE) method to manufacture nanostructures with a characteristic size below 20 nm. For context, ALE is a technique used in semiconductor fabrication which removes one atomic layer at a time from the material surface (in this case, a Silicon wafer) by exposing it to a reactive gas/plasma. 

The newly discovered method at AlixLabs allows ALE to be selectively performed on inclined surfaces – which in turn can be fabricated by epitaxial growth and dry etching. Our task was to get an approximate of how GaP (Gallium Phosphide) will be etched if chlorine (Cl) was used as the plasma and obtain the values of surface energy required for it. To achieve this, we used the Espresso and Jaguar software provided through Schrödinger, which allowed us to build a GaP crystal and turn it into a slab having some amount of vacuum space. Upon adding a Cl2 molecule into this vacuum and by importing pseudopotentials of Gallium, Phosphorus and Chlorine, we ran the chlorination simulation on the software.  

The goal at AlixLabs is to research more about the etching process on inclined surfaces of GaP wafer to make it more widely used and cost-efficient. By running simulations of its etching using different variations of plasma, including Chlorine, we were able to have approximate values of how much energy consumption is needed. Furthermore, by doing SEM analysis and Ellipsometry, we were also able to study the width of the wafers after each round of etching. The ALE process, devised by AlixLabs, has the potential to make nanostructures smaller than 20 nm – which will enable the placement of more transistors on one chip, allowing for an even faster response time for devices. 

If successful in enabling this new method of ALE for large-scale use, this would be an economically affordable method and will also produce fewer by-products which are not sustainable. The faster response time and increased longevity of all the devices which use semiconductors, such as mobile phones and medical devices, will also contribute to reducing e-waste. The key challenge is increasing the consistency of the etch rate and improving the implementation of the Schrödinger software for our desired goal, and increasing the speed of the process.  

Reflecting on our placement 

All in all, we really enjoyed the experience of being able to contribute our part and have this opportunity to travel to Sweden and learn more about AlixLabs and semiconductors. This has certainly deepened our knowledge in this research area, and we are very grateful to continue our alliance with them.

We plan on pursuing the modules of Optoelectronics and Nanomaterials in our years 3 and 4, which have semiconductors at the heart of their foundation. This placement has been a strong starting ground for us to apply the knowledge we have and will gain regarding fabrication and quantum mechanical effects of semiconductors directly into research.   

Read Materials Science in the real-world: Insights from our student placement in full

Read Leading a sustainable initiative: Marta Chiapasco on reducing waste in the lab in full

Name: Dr Max Attwood

Position: UKRI Quantum Technology Career Development Fellow in the Department of Materials.

Research Focus: Developing organic materials for quantum technologies and a type of quantum sensor called the “maser”.

Can you tell us more about your research area?

My research fellowship centres around developing organic materials for quantum technologies, most pressingly, a type of quantum sensor called the “maser”. These masers are the microwave equivalent of a laser, and the word itself is an acronym for “microwave amplification by stimulated emission of radiation”. Such devices have the potential to amplify extremely weak radio/microwave signals within a narrow bandwidth with extremely high signal-to-noise ratios (SNR).

Masers, originally conceived in the 1950s, have historically been used as sensor components inside space-facing radio telescopes. However, due to their thirsty consumption of liquid helium, which was required to sustain their low-noise characteristics, these classical masers fell from favour after the 1970s, mainly being replaced by cheaper field-effect transistor devices.

Interest in these devices was reinvigorated in 2012 when a team of researchers led by Professor Mark Oxborrow and Professor Neil Alford of Imperial College London demonstrated the world’s first room-temperature solid-state maser.^[1,2] Built using an organic crystal of para-terphenyl doped with the “workhorse” molecule known as pentacene, this work represented a significant shift in terms of the maser gain medium and underlying mechanism governing its operation.

When irradiated with yellow light, one electron in the outermost orbital of pentacene becomes spin-inverted, switching the “state” of the molecule from singlet to triplet. In this triplet state, electrons can exist in one of three distinct energy levels that emerge due to interactions between electrons of the same spin. For some molecules such as pentacene, electrons preferentially occupy the uppermost state due to a process of spin-inversion known as “spin-selective intersystem crossing”, thereby generating a strong population inversion. The difference in energy between the uppermost and lowest energy levels corresponds to a microwave frequency of 1.45 GHz. When a microwave photon of 1.45 GHz interacts with a crystal containing lots of triplet-state pentacene molecules, it “stimulates” an avalanche of electrons from the uppermost energy level to the lowest. This simultaneously produces an emission of photons at 1.45 GHz, effectively amplifying the stimulating photon by several orders of magnitude – enough to produce an electrical impulse in a coupled detector.

Thanks to these findings, masers can be used to help detect any phenomenon that might operate or occur at a resonant microwave frequency. This includes sensing extremely small deviations in magnetic field strength or perhaps a single electron spin-flip. I’m interested in the latter example because of its potential to work in tandem with quantum spin-based technologies, including memory devices and communication networks. Before masers can become competitive with contemporary devices, we must find materials that improve their energy efficiency and reduce the impact of non-signal (i.e., noise) photons naturally emitted by ambient objects. This means testing new workhorse molecules instead of pentacene and new host molecules instead of para-terphenyl.

What are the main aims of your current research?

My research aims to build a library of efficient organic maser systems capable of sensing at various frequencies and under significantly dulcified operating conditions compared to the current pentacene-based maser.

As a chemist, my job involves synthesising and analysing new materials with properties that are open and responsive to maser applications. For new host molecules, we look for systems that are chemically inert while also being able to encapsulate a wider range of “workhorse” molecules at a high concentration. In all cases, the more molecules, the better!

We manipulate these properties by changing the chemical structure of guest and host components and determining maser devices’ operating conditions, sensitivity, and output power. In a perfect world, every photon of absorbed light would produce a triplet state with a population inversion!

How could this research potentially benefit society?

A significant advantage of masers over contemporary high electron mobility transistor (HEMT) or superconducting interference device (SQUID) based microwave sensors is their remarkable signal-to-noise. To achieve low-noise figures, these devices require cryogenic refrigeration however, masers operate at room temperature.

High signal-to-noise means that we require fewer repeat measurements of signals to average out background signals. For example, in electron paramagnetic resonance (EPR) spectroscopy, a technique that uses microwaves to detect electron spins, the signal-to-noise ratios are proportional to where is the number of measurements. If we doubled the signal-to-noise ratios, this would result in 4x fewer scans.

This advantage could be used for equipment like nuclear magnetic resonance (NMR) spectroscopy or magnetic resonance imaging (MRI) scanners in hospitals. Currently, NHS patients can expect to wait for more than three months for an MRI scan, so enabling faster scan times could significantly enhance their availability.

What are the next steps in your research? 

Finding materials that exhibit all the qualities required to build a compelling maser device is complex, and we usually must settle for a compromise.

Often, molecules that exhibit a high triplet yield following irradiation with light have short spin relaxation times. This is because the mechanism that enables the formation of triplets, known as “spin-orbit coupling”, also makes it easier for the spin of an electron to flip. Furthermore, we often find that our workhorse molecules are chemically incompatible with known host molecules. Such issues stem from the fact that polar molecules prefer to interact with other polar molecules (like each other).

Therefore, we often rely on glass-forming materials that provide excellent optically clear media form, but light excitation can cause triplet-state molecules to occupy a disordered and inhomogeneous molecular environment. The consequence is that the spin-spin relaxation time diminishes significantly, causing the spread of emission frequencies to expand, which reduces the output power for any frequency we might like to study. Known as “inhomogeneous broadening”, this effect is minimised in crystals which form highly ordered 3D structures at the molecular level.

One of my primary research goals is to synthesise a universal host that can encapsulate a wide range of candidate maser molecules and significantly expedite the discovery and screening process while also ensuring an ordered crystalline environment. I would also like to build on the available computational tools that can calculate and predict the properties of future maser candidates.

References:

[1]      M. Oxborrow, J. D. Breeze, N. M. Alford, Nature 2012, 488, 353–356.

[2]      J. Breeze, K.-J. Tan, B. Richards, J. Sathian, M. Oxborrow, N. M. Alford, Nat. Commun. 2015, 6, 6215.

Read Quantum Potential: Dr Max Attwood on developing organic materials for quantum technologies in full

Materials Undergraduate student, Sophie Kay, shares more about the importance of a supportive community, finding her place at Imperial and her new role leading a LGBTQ+ radio station for Radio Society.

Thinking back to when I was applying to university, what I was most excited about was societies. Having heard the rumours that STEM degrees are hard work, I was determined to find my people and have a good time.

I first visited Imperial back in 2017, having travelled down to London with my family. It was my first taste of a possible life at university and to say I was excited was likely an understatement. I spent the 200 mile train journey back home scrupulously scanning the Imperial College Union website for the most interesting societies – Cheese Society (now sadly defunct, RIP Big Cheese), KnitSock, Film Society, then I came across IQ. At this point in my life I was just beginning to accept my sexuality and clung on to any morsel of LGBTQ+ representation I could find. I was a pleasantly surprised at how strong its membership was – and even more pleasantly surprised at how gender-balanced the committee seemed to be.

As I grew to accept myself more, I found myself becoming frustrated with the world around me. The joy brought by a strong community of both LGBTQ+ individuals and allies, such as those found in IQ, Imperial 600 and organisations such as QPOCPROJECT should never be underestimated, both in impact and importance. There is surely no shortage of struggles to be had however, the beauty of being in community with others is to help lighten the load of the bad times and make the good times shine brighter.

Earlier this year, Radio Society advertised an opportunity to have a radio show so I just jumped on it! I’ve been making themed playlists just as a hobby for years now and always wanted to share them beyond Spotify without being too awkward about it so it seemed right up my street. I’ve found LGBTQ+ artists, especially female, transgender and non-binary artists, to be severely underrated so I just wanted to spread the word about my favourites so more people could enjoy their music, every Sunday from 9-10pm on icradio.com.

STEM can feel very homogenous at times, and it’s very easy to let imposter syndrome seep in and make you think that because you don’t see people like you often, that STEM is not for people like you. It can also make you feel pretty uncomfortable to be openly yourself, however, if you know that there are people around who are proud of their identity and supportive of building a more accepting environment, that can have a domino effect.

Read PRIDE Spotlight: Sophie Kay on supporting LGBTQ+ students and her new radio show in full

Did you know that just 16.5% of the engineering sector are women? 23 June is International Women In Engineering Day, an international celebration to raise the profile of women in engineering and focus attention on the amazing career opportunities available to girls in this exciting industry. 

In the post below, four women in our fantastic community share more about their careers and how they are helping work towards a better future.

Dr Stella Pedrazzini, Lecturer in Engineering Alloys and Metallurgy

I work on the environmental degradation of engineering alloys. I look into the oxidation and hot corrosion of nickel and cobalt based superalloys and aqueous corrosion of steel. To this day, very few research groups around the world work on corrosion due to the challenges involved in this type of investigation. My research group also consists of mostly women – which is very unique in STEM. I also teach the 1st year undergraduate module in Materials Electrochemistry.

My research group is divided by material: we have people working on steels, on nickel-based superalloys, on titanium alloys and more recently on zirconium too. The noble metals are the only ones that don’t corrode (…easily!), everything else is worthy of investigation. Some of the work from my own research group has helped inform the corrosion rates of aero-engines, industrial gas turbines, nuclear reactors and medical implants exposed to body fluids.

I’ve been doing Outreach for ten years, including workshops, talks, and experiments. For me, the motivation for Outreach was primarily the lack of women in Science. My aim is to put the word out there that women can do science and engineering too and it’s important to change perspectives from a young age. For example, when asked to draw a scientist, many primary schoolchildren picture Albert Einstein. However, when asked to draw a scientist after I had presented a talk, schoolchildren were more likely to draw female scientists too!

Dr Jang Ah Kim, Research Associate 

Dr Irena Nevjestic, Research Facility Manager

I am the facility manager for the SPIN-Lab research facility in the Department of Materials. SPIN-Lab straddles three faculties at Imperial and the London Centre for Nanotechnology. It is a state-of-the-art hub of magnetic characterisation to study spin-related phenomena which includes equipment for the study of strongly coupled and isolated spins. This combination of techniques is unique and it offers an insight into the fundamental properties of materials but also prospective applications of how these can be utilised.

I meet a lot of different researchers in my role, which I find the most exciting part of running the lab. Since the SPIN-Lab is an open-access facility, I also have the opportunity to work with lots of users on different projects, which I really enjoy. This week, I had the chance to work on something that was completely new to me, which was a great new learning curve!

Dr Reshma Rao, Research Associate

I work on discovering active, stable and low-cost materials that can catalyse green hydrogen production from water using renewable electricity.

I use a range of operando techniques to understand how such materials function and degrade under the harsh operating conditions they experience in water electrolysers. The term operando (Latin word for working) refers to a class of analytical techniques where a catalyst under operating conditions is monitored in real-time and simultaneously characterizes its activity as well as selectivity. Using this atomic-level insight, I design next-generation catalysts for applications in water electrolysers that can enable green hydrogen production on a large scale.

One of the most exciting aspects of research is that my days are varied. Outside the laboratory, I work on data analysis, facilitate discussions of research projects in small groups, draft manuscripts to communicate my results to the wider scientific community and mentor several students. I’m also fortunate to have the opportunity to travel to present my work at conferences and collaborate with researchers at other universities!

Read Celebrating International Women In Engineering Day in full

Name: Anjali Devadasan

Position: Undergraduate Student

Anjali  is leading a new start-up called EVA Turbines. The start-up looks into how to decrease greenhouse emissions by generating low-cost renewable energy on the roads. Since its creation, the team have reached the semi-finals of the WE Innovate programme and received offers from Hackspace and Enterprise Labs.  

In this blog post, Anjali explains more about her experience and what inspired her to lead the start-up.

Can you tell us more about your start-up project?

Our project, EVA Turbines, aims to decrease greenhouse emissions by generating low-cost renewable energy on the roads. EVA is an efficient, recyclable, vertical axis wind turbine which rotates due to the air turbulence of passing vehicles.

We are at the early stages, currently prototyping our minimum viable product, and we are very encouraged by the support Enterprise Labs and Hackspace offers. It has now been around six months since starting the project, and the project was simply an idea/concept when I started with WE Innovate. Since then, I have learnt a lot about business (lean canvas models, value propositions, customer discovery, etc.), met many new, inspiring people and formed a great team.

What inspired you to choose this focus for your start-up?

I would like to positively impact the environment and mitigate Climate Change, so I am interested in using technology to contribute towards this. An initial idea from when I was at school has eventually changed and pivoted to become EVA Turbines. This project will likely continue changing as we keep adding ideas and learning from others, but our focus on mitigating Climate Change will always be present.

What is it like leading an interdisciplinary team?

It has been exciting forming the team and working together on the project. We are all passionate about Climate Change and dedicated to making a difference. My team member Yu is also studying Materials Science in my cohort. He focuses on product engineering, having previously worked on other projects such as racing drones and AR glasses. As we are both studying Materials Science, it is interesting when we can apply materials science knowledge to the turbine blades and other components. Ukendar is managing turbine design and development, being our mechanical engineer with experience designing projects such as a 3D-printed sensor for the blind. Mariam studies Geography at King’s College London. She is involved in branding, communication and data analysis, with previous projects related to climate change research, such as a policy proposal for zero-emission vehicles. Having a diverse, interdisciplinary team is exciting, as it means we have a wide range of ideas, can learn from each other and work together to build our skills.

What did you learn and how will this help you in future?

I have learnt a lot from the team, mentors, and the many inspiring start-ups at Imperial. Being part of WE Innovate with an idea is like being on a flowing river; I have been gently pushed forward out of my comfort zone every step of the way. The business coaching, masterclasses and modules have been invaluable, and I especially enjoyed the masterclass about effective communication during pitching, which involved two magicians from Breathe Magic teaching us magic! I am truly grateful for the opportunity and would recommend everyone to explore their ideas further with the Enterprise Labs. As a team, we can continue implementing the lessons learnt about business and prototyping for the project and further explore the venture with Climate Launchpad.

I have learnt a lot from reaching out to others and learning from their experiences, so if you would like to have a conversation, please feel free to reach out.

Read Revolutionising Green Mobility: Anjali Devadasan on leading a new start-up in full

In this post, Nomaan Nabi, Research Postgraduate in the Department of Materials, explains more about Ramadan and how he balances fasting with his research during the holy month.

My name is Nomaan Nabi and I am a Muslim student in the final year of my PhD in the Materials department. I work in the field of energy storage in the Electroceramics group supervised by Professor Stephen Skinner and Dr Ainara Aguadero.

As some of you may know that last week the Holy month of Ramadan began, upon the sighting of the crescent moon. Below I’ve outlined a few common questions about Ramadan and life as a Muslim student during this month.

Can you tell us more about Ramadan?

Ramadan is an extremely special occasion for Muslims as it is a time for God-consciousness, forgiveness, charity, and self-discipline. The month is not only about dry fasting from sunrise to sunset but also about, keeping up with daily prayers, avoiding speaking ill of others and using foul language. At the end of the month, we celebrate Eid al Fitr.

How long do you fast for?

We begin our fast before the first prayer of the day known as Fajr Salah which is before sunrise. We end the fast at sunset. The time during the day for fasting depends on your geographical location with people furthest away from the equator having to fast the longest. This is typically done for thirty consecutive days.

How do you break your fast?

Iftar is the time when we end the fast. Traditionally we break our fast with a date followed by the prayer at Sunset known as Maghrib Salah and then you can have the rest of your meal. As one of the purposes of Ramadan is to put yourself in the shoes of the less fortunate, we try to not have a vast amount of food when we can start eating. I think I can speak for all Muslims one of the greatest feelings at the end of each fast is the first sip of water and a date.

When did you start fasting during Ramadan?

I was fourteen years old when I first started fasting. Growing up in Scotland, fasting was something I dreaded as it was during the long summer days. However, as I get older it is always a time I look forward to, as I begin to further understand the benefits whether spiritual or health.

Can you tell us about student life during Ramadan?

The life of a Muslim student during Ramadan can vary a lot from periods of productivity, to becoming quite sluggish as you become dehydrated throughout the day. However, the majority of Muslims during Ramadan go about their day as normal.

Now is a good time as many students are on holidays and hopefully get to spend time with their family and friends.

What will you do this year for Ramadan?

Personally, I tend to stay active in the laboratory, and by the end of the month, I realise how much work is accomplished. As I will be away from my family this Ramadan I will be breaking my fast and praying with fellow Imperial Muslims in the prayer room at College.

Overall, Ramadan is a time for self-improvement and achieving spiritual goals that will hopefully last a lifetime.

If you have any questions regarding Ramadan, you can always approach a Muslim colleague as I am sure they will be more than happy to answer your questions or point you to a more knowledgeable source.

Read PhD Spotlight: Nomaan Nabi on student life during Ramadan in full

Dr Anna Klöckner is a Marie Skłodowska-Curie Fellow in the Department of Materials. Her research focuses on finding novel treatment strategies to overcome the problem of antibacterial resistance. She works within the Stevens Group and the Edwards Group (Microbiology, CMBI). 

In our latest blog post, Dr Klöckner shares more about her research and the fight against a potential global health crisis.

Can you tell us more about your research area?

The discovery of antibiotics was one of the milestones in medicine. By preventing and treating bacterial infections, these drugs saved millions of lives. In the Golden age of antibiotic discovery (around 1940-1960), many antibiotics were discovered and introduced in the clinic with the misleading assumption ‘to close the book of infectious diseases’. Instead, bacteria have been striking back by getting more resistant to antibiotics and making these once-powerful weapons blunt. Infections caused by multi-drug resistant bacteria often require higher antibiotic concentration and more prolonged treatment courses that come alongside severe side effects for the patients.

With the challenges of finding new antibiotics alongside fewer investments in R&D, we may head towards the next global health crisis caused by multi-drug resistant bacteria. It is now vital to use multidisciplinary efforts to find new ways to treat bacterial infections. Over the last few years, more and more researchers have started investigating bioengineered drug delivery systems in which drugs are encapsulated into particles or scaffolds as an alternative to conventional antibiotic therapy.

What are the main aims of your current research?

Finding novel treatment strategies to overcome the antibacterial resistance problem is a significant team effort. As a microbiologist, I experience difficulties finding new antibiotics, and I know the importance of looking at the problem from different angles.

Over the past years, I have been working on bioengineered drug delivery systems to make our existing antibiotics more efficient. The treatment of multi-drug resistant bacteria often requires a more prolonged and harsher antibiotic course, which can cause side effects and interfere with the patient’s microbiota.

In my research, I focus on drug delivery systems made of multiple compartments that can be loaded with an antibiotic. They look like a flower and act like little trucks carrying goods. Thereby, the trucks protect the cargo from the environment and vice versa. A significant drawback of antibiotics is that they do not selectively kill harmful bacteria and often affect our good microbiota. To avoid that, it is vital to release the antibiotic from the drug delivery system only at the side of infection.

The beauty of our drug delivery system is that an on-demand release mechanism was introduced, which is triggered by molecules that are only produced by pathogenic bacteria. This guarantees a very local antibiotic exposure which protects most good bacteria in the human body. Over the last years, more research has shown that using a combination of antibiotics to treat pathogens often leads to a better outcome than single antibiotic therapy.

The difficulties in antibiotic combination therapy are that both drugs simultaneously reach the side of infection in a high enough concentration. Due to the multiple compartments of our system, it is straightforward to deliver numerous medications in the same area, guaranteeing the bacteria’s exposure to both drugs at the same time. Therefore, drug delivery systems can provide a promising approach to carrying multiple antibiotics and releasing them only where needed. They would be safer and more efficient than their free antibiotic counterparts.

How could this research potentially benefit society?

The Covid-19 pandemic showed once more how devastating a global pandemic can be for society and economics. Before discovering antibiotics, bacterial outbreaks were frequent. With the plaque holding the dark record as one of the most fatal pandemics in human history, we should not underestimate the threat caused by bacteria. With antimicrobial-resistant bacteria on the rise and the challenge in discovering new antibiotics, there is a chance that history will repeat.

The last decades revealed that the golden age of antibiotic discovery is long over and not many new antibiotics made their way into the clinic.  Bioengineered antibiotic delivery could help overcome the limitation of our currently existing antibiotics and use them more efficiently. The drug delivery system I am working on is versatile and tailored towards a specific bacterial infection. The delivery of multiple antibiotics and the local release of drugs antimicrobial-resistant bacteria could be targeted easier by simultaneously preventing the interruption of the patient’s healthy microbiota. Therefore, drug delivery systems are a promising way to improve our current antibiotic treatment regime and help to solve the antimicrobial-resistant crisis.

What are the next steps in your research? Are there any challenges ahead?

We are in the early stages of developing this type of drug delivery system, where we showed the triggered release of multiple antibiotics and the resulting antibacterial activity in a laboratory environment. We are currently tailoring the drug delivery systems towards specific bacteria classified by the World Health Organisation as critical due to their resistance to antibiotic therapies. Therefore, new release mechanisms, drug combinations and materials for the assembly of the compartments are under investigation.

The immediate next steps would be to test the drug delivery system in an animal infection model to see whether the antibiotic delivery works in a more complex environment. The longer-term challenges are upscaling the production without losing the quality of the drug delivery system by keeping the production costs low and finding the ideal route of administration.

Overall, there might be a bumpy and long road ahead of us before this type of drug delivery system makes it into a real-world application. Still, if that means we are one step closer to overcoming the antimicrobial-resistant problem, it is worth it.

Read Research Insights: Interview with Dr Anna Klöckner in full

Dr Sam Humphry-Baker is an Imperial College Research Fellow in the Department of Materials. His research lies at the intersection of materials science and fusion engineering, where he develops new materials that can enable fusion energy reactors to be deployed on a smaller scale.  

In this blog post, Dr Humphry-Baker shares more details about his research and passion for fusion energy.

Can you tell us more about your research area?

My research supports the development of fusion energy. In the past, fusion reactors have been very large and expensive to build, which has meant progress with the technology has been slow. However, recent developments of more powerful magnets have meant that the reactors can be made much smaller than previously.

The shrinking of the reactor leaves certain components more exposed to damage from high energy particles being produced by the fusion reaction. Usually, these components are protected by shielding, but current shielding materials are optimised for conventional nuclear power, so these components will begin to degrade within weeks or months. It is therefore important that new, more efficient shielding materials are developed.

My research seeks to design these materials so that the lifetime of the reactor can be extended to decades to enable commercial power production. My team and I at Imperial are designing new ceramic materials with orders of magnitude increases in reactor lifetime over conventional materials. This work is carried out in collaboration with leading fusion engineering companies like Tokamak Energy Ltd, as it is important to consider the issues involved with integrating these new materials into a real engineering system.

Once these materials have been designed on the computer, we must address the key scientific and engineering challenges governing their practical use. This is critical as these materials are not used industrially. Therefore, there is limited understanding of how they can be manufactured and how they will behave in the extreme conditions of a fusion reactor.

What are the main aims of your current research?

The first aim of my research relates to the manufacture of the materials. Because they are not widely available, we must develop a new understanding of how the fabrication variables can be optimised to gain optimal performance in the material. These ceramics melt at very high temperatures; therefore, we must build them up from powders. My team and I do this by fusing the powders together under heat and pressure, similar to how many high-temperature components like space shuttle tiles are made.

The second aim of my research is to demonstrate performance in reactor-like conditions. The key challenge is that they will be bombarded by high energy particles in the reactor. This is particularly damaging in a fusion reactor as the particle energy is much higher than in a conventional nuclear reactor. The bombardment tends to jumble up the arrangement of the atoms, which can make the materials more brittle; in the same way that when you bend a paperclip back and forth, it can eventually snap. To test this, we collaborate with experts in computer modelling to understand what kind of jumbling up processes are most important. Then we use specialist particle beam facilities to experimentally see what the jumbling up does to the structure of the material.

The final thrust of my research group is to engineer new composite structures with improved damage tolerance. One of the tricks we have used is to add a cement-like layer between relatively brittle ceramic particles. These kinds of structures are commonly found in nature; for example, sea-snail shells are built from thinly stacked layers of relatively brittle chalk-like ceramics, with a gluey substance in between. So, when predators strike the shell, cracks tend to stop in the glue, and the snail survives. Obviously, shells have had several million years of evolution to optimise their structure, whereas we must do it in a much shorter timescale, which is challenging but also exciting!

How could this research potentially benefit society?

My research in developing these materials could enable fusion reactors to be built at a much smaller scale than previously possible, meaning privately funded companies can now get involved for the first time. This accelerates the rate at which fusion energy can be rolled out in the future. For example, companies like Tokamak Energy and General Fusion plan to build energy demonstrating reactors in the 2020s. This is much earlier than the equivalent front running energy demonstrating fusion reactor being planned by international government collaboration, which is planned for 2050. Accelerating fusion’s development could allow us to help the UK in meeting its ambitious carbon emission targets.

Many of the environmental benefits of fusion are shared with renewable energy technologies like wind and solar. However, fusion has additional advantages in that there is no need for costly long-term storage for when it’s dark, or the wind isn’t blowing. Furthermore, since electricity only represents about a fifth of the UK’s energy usage, we must decarbonise our substantially larger needs from heating. Small fusion reactors could do this by heating our homes through district heating systems and powering challenging processes like steelmaking as they will operate at a much higher temperature than conventional nuclear reactors. A further advantage over conventional nuclear is that there is no risk of a reactor meltdown, and the waste produced is safe to handle and recycle after a much shorter time.

I recently attended the Earl of Wessex Future Energy Conference to explain my vision for how small fusion reactors can help the UK reach Net-Zero by 2050. My team and I were awarded a prize in the Young Persons energy pitch competition.

Dr Humphry-Baker and team picture with Prince Edward, Earl of Wessex.

What are the next steps in your research? Are there any challenges ahead?

We have already developed the maturity of our first generation of new shielding materials to a fairly high level. The next stage for these materials is to put them in a real nuclear reactor and study their performance in greater detail. These experiments are very costly and require collaboration with dedicated international facilities. We currently have materials sitting in a reactor at the Oak Ridge National Laboratory in the US, and we expect to start getting the first experimental results at some point later in the year, which is very exciting.

Once this work is complete, there are several engineering challenges that must be overcome before these materials can be deployed in a real fusion reactor. For example, we must develop new ways to join them to structural elements in the reactor and understand how they interact with coolants, which can often be corrosive.

Materials science is at the heart of many of these challenges, but solving them will require collaborating with a huge array of different engineers and scientists in the future. Interacting with these people keeps me fresh and energised to do this research!

Read Shaping the Fusion Future: Interview with Dr Sam Humphry-Baker in full

Ritika Vastani is a Research Postgraduate in the group of Professor Stephen Skinner. In Spring 2020, Ritika and her research group took part in the LEAF framework, an initiative created at UCL to improve the sustainability and efficiency of laboratories. The group received a bronze award for their efforts.

In our latest blog post, Ritika shares more about her experience and the small steps you can take to improve sustainability in the lab.

1. What inspired the group to get involved with the LEAF programme?

As a research group that works towards materials development for new energy technologies, we understand the growing importance of combating global warming and climate change. Whilst most people associate sustainability with the environment, I believe that becoming sustainable is a part of our daily life choices. I saw the LEAF programme as an opportunity for our group to become more sustainable because research laboratories are resource and energy-intensive. As a group, we decided to work towards achieving the bronze award, and through fortnightly group meetings, we discussed where improvements were needed in our research lab.

2. How did you maintain a collaborative effort towards sustainability?

All group members were involved in improving sustainability within the lab. We had two nominated people in our group to drive sustainability forward, and the remaining members were appointed to oversee one of the criteria in the framework. Frequent group meetings played a significant role to discuss and identify our areas for improvement and we were able to update each other on our progress. Most importantly, fortnightly lab cleaning allowed us to work together to achieve the criteria which we identified to take longer, i.e. tackling or discarding waste materials left by departed students and staff. These efforts combined encouraged us to work as a team and achieve the bronze award.

3. What changes did the group implement in the labs?

The main changes to the lab included creating a new system for sharing of chemicals. To combat this, we set up a Quartzy database to track shared chemicals in which all lab members had access to search and add new inventory. We became more sustainable through encouraging sharing and reducing potential future waste. In addition, we sorted through pre-existing samples, where we then assigned a designated area for older samples. Moving forwards, we implemented an exit form for future departing staff/students. The form allowed us to know the exact location of the stored samples in the lab. Most importantly, visible signage was placed to encourage good practice to lower fume hood sashes, discard chemical waste appropriately, turn off lights when not in use and recycle packaging where we can.

4. What did you learn from the programme?

Taking part in the LEAF programme has enabled us to understand how sustainability is not only dependent on reducing waste and energy consumption. Becoming a sustainable research lab has also relied upon becoming socially responsible in day-to-day life around the lab. For example, the Quartzy database allows current users to input and future lab members to search for existing chemicals. These changes have allowed us to implement sustainable practices around the lab, allowing short-term benefits from an economic prospect and long-term environmental benefits to arise.

5. What advice would you give staff and students looking to improve sustainability in their labs?

Taking part in the LEAF programme is an excellent opportunity to improve sustainability in your research lab. As a student who is driving sustainability forward in our group, it is important to work as a team to implement sustainable practices.

The LEAF programme is now available for any research institution looking to improve their sustainability, including outside the UK. If you are interested in taking part, please email LEAF@ucl.ac.uk for an introduction and information on how to get involved.

If you would like to learn more about sustainability at Imperial, please visit the college website for more information.

Read Time to turn over a new LEAF? Research Postgraduate Ritika Vastani on improving sustainability in the lab in full