Text: Elina Venesmäki

Could lost heat be recovered more efficiently? This is the subject of research for Ph.D. Antti Karttunen and Ph.D. Maarit Karppinen and their teams at Aalto University.

The Finnish Cultural Foundation decided to grant EUR 1,25 million euros in funding on the theme of “new materials and technologies for the green transition”. Karttunen and Karppinen’s teams were among the grantees.

“We are researching how to turn heat loss into electrical energy,” Karttunen says.

Say someone burns wood in a fireplace to save on heating energy, for example; could they collect the extra heat and turn it into electricity to charge their phone?

Our researchers are looking into this. Server rooms, for instance, generate huge amounts of heat, but usually it is fanned out. In Finland it is used for heating in winter, but at other times and in other parts of the world it is mostly just lost.

That doesn’t have to be the case. The scientists are focusing on a technique called atomic layer deposition (ALD), which creates thin films. These are used to turn heat into electricity.

Karttunen demonstrates a device smaller than a mobile phone, that is already capable of doing so.

The technology is already 50 years old, but it has two problems: first, it is not very efficient; second, it involves rare metals, which means it cannot be universally applied.

These are the issues Karppinen and Karttunen are looking to solve in order to make the technology widely reproducible.

“We want to use a material that appears commonly in the earth’s crust, such as iron,” Karttunen says. The metals currently used in the devices are also toxic, so they are searching for a safer material.

Heat loss is everywhere

An electric car’s batteries produce heat loss, as do industry, computer rooms and even the human body. Could a film created through ALD be added to a sports shirt and the heat generated during a gym session be used to charge a mobile phone?

“Collecting heat from a gym shirt is a small step, of course. But electric car batteries and data centres generate huge amounts of heat that is wasted in most parts of the world.”

These issues mentioned earlier must be solved before anything major is created. So where could one find a commonly available, safe material, and how does one make the device as efficient as possible?

The research team has access to an ALD machine around one metre in width, height and depth. A test piece can be placed inside, and it will be coated in a film that collects heat and turns it into electricity.

“Green steel production is currently a hot topic. Soon steel manufacturers will be able to use hydrogen, which will cut carbon dioxide emissions. This is fine, but it will still generate huge amounts of heat loss,” Karttunen says.

Novel solar cells

Professors Jussi Toppari and Gerrit Groenhof and their research teams at the University of Jyväskylä are also working to further the green transition. They received the same funding to create more efficient and ecological solar cells.

Currently there are two types of photovoltaic cells: organic and inorganic (semiconductor-based).

The efficiency of organic solar cells is only just over 10 per cent. Semiconductor-based solar cells are mostly seen on ordinary roofs because they are much more efficient and durable than organic ones, but even their efficiency is not great. Typical silicon solar cells capture and process around 30 per cent of the energy radiated by the sun.

Toppari and Groenhof want to take this further: they want to collect energy from a large area onto one or a handful of molecules, from where it goes into storage.

“We are already able to make molecules transfer the energy they receive from light really efficiently from a large area onto one molecule. The bottleneck is how to move it on from there,” Toppari explains.

Target: more power

The subjects of study here are on a very small scale, measured in nanometres (one billionth of a metre).

There are many molecules that can collect photons, i.e. absorb light. Having absorbed a photon, the molecule becomes energized. It can transfer this energy on to another molecule, for example, or emit an electron, which creates an electrical current. This is the operating principle of some organic solar cells.

“We are taking this further in that the photons are not absorbed directly into the molecules but become coupled with metallic nanostructures. This turns the light into a surface plasmon, which becomes coupled much more strongly and with several molecules at a time.”

The surface plasmon and the molecules form a single space among which the energy spreads. This permits high-speed energy transfer between the molecules. The scientists intend to utilise this property in a new type of cell.

They have already demonstrated that light can couple with several molecules. This three-year grant period will focus on how the energy can be passed forward once it is collected.

“This period gives us time to build a prototype and prove that it works.”

Teksti: Emma Nikander

Ancient DNA can reveal a lot about the history of people and the environment. At the same time, it can provide answers to some of today’s most pressing questions, such as biodiversity loss, climate change and pandemics.

The boring of sediment samples from the soil provides data from a very long time period: so long that it could not be accessed in any other way. For example, the deepest sediments of our 10,000-year-old Baltic Sea contain records of the sea’s whole history. Samples can be used to study the sea’s ancient and current organisms and to obtain information on the state of the environment during various periods.

Geneticist Petri Auvinen and his team are running a project examining two types of samples that take them on a journey far back through time. In addition to sediment samples from the Baltic Sea, they are boring a second series of samples from a bog in Tammela, whose deepest parts can provide data on a similarly long period.

If DNA can be isolated from these samples, scientists can examine it for evidence of the historic microbes, flora and fauna of the region. The samples may also show what the soil was like and what happened to it when the climate changed.

This may help us to understand our current climate change, Auvinen explains: “It is easier to predict the future when you know what has happened in the past. Marine sediments and marshlands have been recording conditions for thousands of years without asking any questions. In this case, we can use history to reach into the future.”

What did the people buried at Levänluhta die of?

Studies of ancient DNA can also provide valuable information on people’s lives. A project conducted by Professor Antti Sajantila and his team is examining ancient DNA from remains recovered from two different kinds of burial sites from different periods. These are the tar pit grave in Ruukki, south of Oulu (northern Finland), and the waterlogged burial site of Levänluhta in Isokyrö (South Ostrobothnia) and the nearby Käldamäki burial site.

Besides the people who died, the team is interested in the viruses and bacteria they carried. By studying the human and pathogen DNA in the remains, the team is seeking to find out who the deceased were, what population group they belonged to and anything about their state of health or cause of death. They also want to know when the people lived and what they ate. Were they related? That can also be revealed using molecular research.

The Levänluhta burial site has been known since the 1670s, and it has been investigated using different methods for over a century. Diverse theories as to how the bodies ended up there have been suggested over the years, explains Professor Antti Sajantila of the University of Helsinki.

“The Ruukki area seems to be a burial site from a specific time period, whereas Levänluhta appears to contain remains spanning several centuries of the Iron Age.  And not just human remains but also animal ones. Perhaps our research will show whether they died of an epidemic or of malnutrition, for example.”

The multidisciplinary research team includes experts in molecular genetics, forensic pathology, molecular virology and isotopes, as well as archaeologists. “Information produced by a single discipline would be significantly less valuable without the other fields to support it,” Sajantila says.

Data on the movements of hops and apples

Information on ancient peoples and their ways is not only obtained by studying human DNA. Samples found at two archaeological sites – Stone Age Humppila and Medieval Turku Cathedral School in Finland – may generate data for example on the strains of hops and wild apple used in Finland. They are being studied by biologist Sanna Huttunen and her team at the University of Turku.

“We are trying to find out, among other things, what strains were used in various parts of Finland, are they related to today’s heritage or wild varieties, and how they spread,” Huttunen explains.

This information will then be compared with historical and modern data possessed by scientists at the Natural Resources Institute of Finland, Finland’s museums of natural history and individual researchers, among others, who are partnering with the project.

In Humppila (southern Finland), Stone Age strata have become buried in layers at the bottom of a paludified (filled-out) lake. The flora and fauna preserved in the peat can now be identified more accurately than before, using DNA barcoding. After that the team can examine whether they show evidence of settlement from 4,000 years ago. DNA methods can also be used to identify flora and animal remains that have previously not been recognised. This can show whether some of them were farmed grains, for example.

“That would be one of the earliest signs of agriculture in Finland,” explains the team’s archaeologist Mia Lempiäinen-Avci from the University of Turku.

Hops were very widely grown in the Middle Ages – almost by every household. Genetic data can show us how people spread various strains of the plant. Here, too, the past can help us equip for the future: if a specific strain of hops appears to have survived through the ages, it may have potential to cope well in the uncertain times ahead.

The samples are already in existence, so there is no need for new digs. Therefore the project will focus on examining them with microscopes and in labs, Huttunen explains. Every member of the multidisciplinary research team has their own areas of responsibility and expertise.

“The starting point for the research was that we have access to expertise and diverse data that can be seamlessly combined to achieve results that no one could produce by themselves.”

Demand for ancient DNA research

The 2022 Nobel Prize in Physiology or Medicine went to biologist Svante Pääbo, who ran research that revealed the Neanderthal genome and led to the discovery of a whole new human species. The prize had a significant impact on the status of ancient, environmental and sedimentary DNA research, mentions Sajantila, who himself worked in Pääbo’s laboratory at one point.

Until now, ancient DNA research has lagged behind in Finland, and our extensive bodies of data have been under-researched, according to Lempiäinen-Avci. “I am thankful that the Finnish Cultural Foundation supports this highly necessary topic.”

“This kind of research teaches us to value our history and our special characteristics. All sorts of things may be revealed once we begin to examine data that has previously received little attention,” Huttunen explains.

In 2023, the Finnish Cultural Foundation granted EUR 2 million in funding to research projects focusing on ancient, environmental and sedimentary DNA. The aim was to increase cooperation between research teams from various disciplines, thereby strengthening the field as a whole in Finland.