Henrik Ottosson group

Physical and theoretical organic chemistry in excited states (for sustainability).

Our research

We have a strong research focus on excited state aromaticity and antiaromaticity, both the fundamental aspects as well as the utilization of these concepts in a range of applied areas that span from pharmaceutical chemistry to photovoltaics. Indeed, the group has carried out research on excited state (anti)aromaticity effects for more than 20 years and has an internationally leading position in the area. Yet, we also have a broader interest in organic photochemistry related to solar energy conversion and storage. For instance, to form sustainable aviation fuels (SAFs) directly from CO₂, water and sunlight through a combined photobiological-photochemical route that we have developed together with biotechnology colleagues. Expanding beyond Chemistry, Henrik has furthermore a deep interest in urban science and urban sustainability, and he is in the process to link activities in this area to the photochemistry research of the group.

We carry out both experimental and computational/theoretical studies, and have an extensive network of national and international collaborators.

Our research, teaching and other activities can be categorized in four partially overlapping areas:

Excited state (anti)aromaticity: Fundamentals & applications

It has been estimated that about two thirds of all known chemical compounds are aromatic or partly aromatic. Thus, the concept of aromaticity is core to chemistry, especially organic chemistry. Yet, it is also a so-called fuzzy concept that cannot be uniquely defined or described, and it gets even fuzzier if one moves to electronically excited states.

The Ottosson group explores the various forms of excited state aromaticity and antiaromaticity (ESA & ESAA), and their scopes, limitations, complications and pitfalls. Yet, with this fundamental knowledge in the rucksack they also make use of the concepts to rationalize and develop new photochemistry and optically active molecules. The concepts should have a huge potential in this regard.

Organic photochemistry for solar energy conversion and storage

With interests in the photophysical and photochemical properties of π-conjugated organic molecules an obvious application area is solar energy conversion and storage.

The excited state properties of the molecules which the Ottosson group utilize either rely on excited state aromaticity or on excited state characteristics that are desirable for a specific photoreacticity. This is exemplified with, respectively, (i) design of novel chromophores for potential use in singlet fission photovoltaics, and (ii) development of new photocatalyst systems for formation of solar SAFs. Although the project goals are applied, these projects closely link to fundamental investigations of the group and aims to bring solar energy research in new directions.

City-integration of chemistry-based renewable energy technologies

Since a few years Henrik teaches a Chemistry MSc course on Renewable Energy Technology & Society covering the social and societal aspects of the green energy transition; opportunities as well as challenges. Focus in the course is placed on chemistry-based technologies for conversion and storage of renewable energy.

Today, cities are main consumers of energy, while renewable energy is often produced at more rural locations. The future will likely demand more city-integrated renewable energy production, and (photo)chemistry, materials science and biotechnology provide technological opportunities for more efficient production of energy which is required for this. Yet, this technology when city-integrated may come with challenges from social sustainability perspectives.

Illustration of renewable energy in a city

Urban sustainability (UN Sustainable Development Goal Number 11)

Since high school Henrik has had an interested in architecture, the built environment and cities, and Uppsala has provided a perfect platform to nurture that interest in parallel to the Chemistry research. It started with a debate article in the local newspaper in 2009 and has gradually developed into research activities (special interest urban morphology and societal impacts). From 2019 till the end of 2022 he coordinated the Urban Sustainability initiative, one of five university-wide initiatives within the Uppsala University Sustainability Initiatives (UUSI). He regularly interacts with researchers at the Institute for Housing and Urban Research (IBF) of Uppsala University, and in February 2024 he spent a brief sabbatical at The Bartlett School of Planning, University College London.