Maarit Karppinen appointed Academician of Science

Professor Maarit Karppinen of Aalto University has been appointed Academician of Science, the highest title a researcher can receive in Finland. The title is awarded by the President of the Republic of Finland on the proposal of the Research Council of Finland (RCF) and can be held by no more than 16 Finnish scientists at any one time.

Karppinen is known for her pioneering work on atomic layer deposition (ALD) and molecular layer deposition (MLD) of inorganic–organic thin films. She was awarded the honorary title of Aalto Distinguished Professor in 2017 and has served on the Scientific Council of the European Research Council (ERC) since 2025.

For Karppinen, the title of Academician of Science represents the highest possible recognition of her work.

“If someone had asked me what the best possible thing I could achieve in my research career would be, I would have said something like this – a recognition based on scientific merit,” Karppinen says.

Her appointment is particularly notable, as she is actively working as a professor. The title is typically awarded to researchers who have retired.

A researcher of new materials

Karppinen describes herself as first and foremost a researcher focused on fundamental research. Her career has focused above all on investigating new materials.

“People use the term ‘new materials’ to mean many different things, but to me, a new material is a material or compound that no one has ever made before. That has always been what interests me most,” Karppinen says.

Over the course of her career, the materials she has studied and the applications they could enable have varied. Her research has included materials for energy technologies, semiconductors and microelectronics.

A decade in Japan studying superconductors

Karppinen’s research career has taken her from Aalto to Japan and back, including approximately ten years spent working in Japan.

In 1991, she went to Japan to study new high-temperature superconductors. The field was attracting considerable attention worldwide at the time, and Karppinen was one of the very few chemists in Finland researching superconductors.

“In the early 1990s, there were not many connections between Finland and Japan. Japan was an excellent place to work on superconductors. I was the only woman and the only European among around 100 researchers,” Karppinen says.

The connections she made as a doctoral researcher eventually led to a visiting professorship at Tokyo Institute of Technology and later to a permanent professorship.

Throughout her years in Japan, she maintained her ties with Aalto, and Finnish students continued to work with her research group.

Returning to Finland and developing ALD/MLD

When Karppinen returned to Finland in 2006 to take up her current professorship in inorganic materials chemistry, she returned to a laboratory with a long tradition of atomic layer deposition (ALD) research.

Developed in Finland, ALD is a technique used to produce high-quality inorganic thin films, particularly for microelectronics. It has helped make possible the development of increasingly powerful and compact computers, smartphones and other everyday devices.

“After returning to Finland, I became interested in finding ways to expand the range of materials that could be produced using ALD. I did not want to focus solely on relatively simple inorganic thin films for microelectronics applications. I wanted to use ALD to create new materials,” Karppinen says.

Karppinen combined ALD with a technique now known as molecular layer deposition (MLD). This makes it possible to produce hybrid thin films that combine organic layers with inorganic ones. Her research group has developed numerous new ALD/MLD processes.

“At best, these inorganic–organic hybrid thin films allow us to combine the best properties of inorganic and organic components in a single material. This can give rise to entirely new material properties,” Karppinen says.

The combined ALD/MLD technique can, for example, be used to make thin films flexible, less thermally conductive or capable of absorbing light in specific ways. Such tailored thin films are being developed for applications including microbatteries, solar cells and thermoelectric devices.

Nearly 50 doctoral researchers supervised

Karppinen considers supervising nearly 50 doctoral researchers to be one of the most important achievements of her career.

“I greatly value the title of Academician of Science, as well as my membership of the ERC Scientific Council. I would never have imagined beforehand that I would achieve either of them. But ultimately, what I am most proud of is the doctoral researchers I have supervised,” Karppinen says.

Many of the researchers who have completed their doctorates under Karppinen’s supervision have gone on to work in industry. As they move into professional life, they take their research expertise with them, potentially influencing their fields for decades to come.

“What an individual professor can achieve is fairly limited. Ultimately, the greatest impact of our work comes from the cumulative contribution of the students we train and the things they go on to achieve.”